Porous 4 group metal oxide and method for preparation thereof

ABSTRACT

This invention relates to a 4 group metal oxide and to a method for preparation thereof and the 4 group metal oxide prepared by adding a particle growth inhibiter to a hydrosol a hydrogel or a dried product of a hydrous 4 group metal oxide represented by MO (2-x) (OH) 2x  (wherein M denotes a 4 group metal and x is a number greater than 0.1 or x&gt;0.1) followed by drying and calcining has a specific surface area of 80 m 2 /g or more, a pore volume of 0.2 ml/g or more and a pore sharpness degree of 50% or more and excellent heat stability and is useful for a catalyst or a catalyst carrier in which a catalyst metal is dispersed to a high degree. This invention further relates to a porous 4 group metal oxide and to a method for preparation thereof and the 4 group metal oxide prepared by application of a pH swing operation is characterized by a large specific surface area, excellent heat stability, high dispersion of a catalyst metal and a controlled and sharp pore distribution and is useful for a catalyst or a catalyst carrier of excellent reaction selectivity.

TECHNICAL FIELD

[0001] This invention relates to a porous 4 group metal oxide which isuseful for applications such as catalyst carriers, catalysts, dryingagents, adsorbents and fillers, to a method for preparation thereof andto applications thereof. In particular, this invention relates to aporous 4 group metal oxide which has a large specific surface area andexhibits excellent heat stability, to a method for preparation thereofand to applications thereof.

[0002] Further, this invention relates to a porous 4 group metal oxideconsisting of high-purity porous titanium oxide which has a largespecific surface area, exhibits excellent heat stability, has preciselycontrolled pore size and sharp pore distribution and is useful for acatalyst carrier or a catalyst and to a method for preparation thereof

[0003] Further, this invention relates to a porous 4 group metal oxideconsisting of porous titanium oxide which has a large specific surfacearea, exhibits excellent heat stability, has controlled pore size,exhibits high mechanical strength and is useful for a catalyst carrieror a catalyst and to a method for preparation thereof.

[0004] Still further, this invention relates to a hydrotreating catalystconsisting of a porous 4 group metal oxide of the aforementioned kind,particularly, porous titanium oxide, for hydrocarbon oils such aspetroleum fractions and liquefied coal to a method for preparationthereof and to applications thereof more particularly, this inventionrelates to a hydrotreating catalyst comprising titanium oxide (alsoreferred to as titanium dioxide or titania) with a large specificsurface area as a catalyst carrier and the catalyst components(consisting of the principal catalyst component and promoter componentand hereinafter both are collectively referred to simply as “catalystcomponents”) which are dispersed uniformly in high concentration on thetitanium oxide, to a method for preparation thereof and to applicationsthereof and, more specifically, this invention relates to ahydrotreating catalyst for hydrocarbon oils which is capable of removingboth sulfur components and nitrogen components from hydrocarbon oils toa high degree while enhancing selective removal of nitrogen componentsrelative to sulfur components and, at the same time, capable of markedlyreducing consumption of hydrogen, to a method for preparation thereofand to applications thereof.

BACKGROUND TECHNOLOGY

[0005] The methods for preparing porous 4 group metal oxides areexplained with porous titanium oxide taken as an example. The methodsknown today are roughly classified into two methods and one is based oncombustion of titanium tetrachloride by oxygen (vapor phase method)while another is based on the preparation of hydrous titanium oxide orthe precursor of titanium oxide in advance by such means as hydrolysisof titanium sulfate or titanyl sulfate, alkali neutralization oftitanium tetrachloride or titanium sulfate or hydrolysis of a titaniumalkoxide followed by drying and calcining the hydrous titanium oxide(liquid phase method).

[0006] Representatives of the aforementioned liquid phase methods arethe following: • where the hydrolysis of titanyl sulfate is resoted to,titanyl sulfate is heated at or above 170° C. and hydrolyzed at apressure equal to or above the prevailing saturated steam pressure toyield hydrous titanium oxide and then the hydrous titanium oxide iscalcined at 400-900° C. to yield spherical anatase type titanium oxide(JP05-163,022 A); • in the case of the neutralization of titanylsulfate, needle crystals of titanyl sulfate are contacted with anaqueous alkaline solution and the resulting needles of hydrous titaniumoxide are dried and calcined to yield titanium oxide in needle crystals(JP05-139,747 A); • In case a sol-gel method involving the hydrolysis ofa titanium alkoxide is adopted, a titanium tetraalkoxide and water aremixed to form a precipitate, the precipitate is filtered, washed withwater, then mixed with water to form a slurry, the slurry is subjectedto a hydrothermal treatment and the product thereby obtained is dried togive mesoporous titanium oxide with a pore volume of 0.1-0.5 ml/g and anaverage pore diameter of 3-30 nm (JP2001-031,422 A).

[0007] However, porous titanium oxide prepared by the aforementionedconventional methods generally shows extremely poor heat stability andpresents the problem of suffering a rapid loss in specific surface areaand failing to maintain a large surface area when subjected tocalcination at high temperature or over a prolonged period of time. Whathappens here is that the hydroxyl groups detach themselves from hydroustitanium oxide and undergo condensation or titanium oxide being formedundergoes the so-called sintering thereby growing considerably incrystalline particles; for example, as shown in FIG. 1 which is a plotof the relationship between specific surface area and calciningtemperature, crystallization or crystal transformation from amorphous toanatase and rutile takes place as the calcining temperature rises and,as a result, the specific surface area decreases rapidly which makes itdifficult to maintain the specific surface area at a high level.

[0008] Under these circumstances, a catalyst carrier or a catalyst basedon titanium oxide, in spite of its extremely high activity forhydrotreating per unit specific surface area, cannot maintain a largespecific surface area at high temperature because of its poor heatstability nor manifest a sufficient performance as a catalyst and,unlike catalyst carriers or catalysts based on alumina or silica, hasnever been utilized commercially.

[0009] Where titanium oxide is intended for use as an alkylationcatalyst, a high-temperature heat treatment is necessary in order toprovide titanium oxide with properties of a superstrong acid; butdeteriorating heat stability and diminishing specific surface area causea decrease m the absolute amount of superstrong acid and the propertiesrequired for a catalyst could not be secured.

[0010] Where titanium oxide was intended for use as a denitrogenationcatalyst of exhaust gases, it could only be used with its specificsurface area limited normally to a low range of 40-50 m²/g because ofits poor heat stability in spite of its excellent denitrogenationactivity per unit specific surface area. Thus, the problems here werethe necessity for using a large quantity of a given catalyst as well asnarrowing of the range of use temperature of the catalyst caused by poorheat stability.

[0011] Moreover, where titanium oxide is used as a catalyst in theFischer-Tropsch (FT) reaction, only titanium oxide with a small specificsurface area was made available in spite of its good abrasion resistanceand it has not been possible to obtain a titanium oxide-based catalystexhibiting satisfactory performance for this particular application.

[0012] Several proposals have been made to solve the aforementionedproblems. For example, attempts have been made to add a secondarycomponent such as silica, alumina and phosphorus to titanium oxide toprepare porous titanium oxide that has a large specific surface area andshows excellent heat stability. The following are examples of suchattempts. According to a proposal made in JP07-275,701 A, a siliconcompound and a titanium compound are dissolved in an acidic solution, abasic substance is then added to cause coprecipitation and thecoprecipitate is aged to give silica-titanium oxide. This methodregulates the ratio of titanium oxide to silica within the range of 1-50wt % (13 wt % of titanium oxide is used in one example) and thesilica-titanium oxide catalyst obtained by 3-hour calcination at 500° C.shows an extremely large specific surface area of 558 m²/g.

[0013] A proposal in JP08-257,399 A is directed to the preparation of atitanium oxide-based catalyst by gelling a hydrolyzed sol of a titaniumalkoxide and a silicon alkoxide with a molar ratio of (1−x)TiO₂.xSiO₂(x=0-0.5) and calcining the resulting gel at 350-1200° C. The ratio ofsilica added to titanium oxide is low in this titanium oxide-basedcatalyst and, in one example, the molar ratio of titanium oxide tosilica (TiO₂:SiO₂) is 0.95:0.05 and the titanium oxide catalyst preparedby 2-hour calcination at 500° C. shows a specific surface area of 160m²/g.

[0014] According to a method proposed in JP2000-254,493 A,silica-modified titanium oxide for use as a catalyst carrier is preparedby allowing a mixture of a titanium alkoxide and a silicon alkoxide toreact in an alcohol solvent and calcining the reaction product. Thissilica-modified titanium oxide for use as a catalyst carrier has anatomic ratio Ti/Si of 5-50 and shows a BET specific surface area of 90m²/g or more even when calcined at a temperature as high as 800° C. orabove. One example give the results that, when the Ti/Si atomic ratio is10, silica-modified titanium oxide obtained by calcining at 600° C.shows a specific surface area of 185 m²/g.

[0015] A proposal made in JP2000-220,038 A relates to the preparation oftitanium oxide fibers containing catalyst components in the followingfour steps: {circle over (1)} a titanium alkoxide is dissolved in asolvent and allowed to undergo hydrolysis and polymerization reactionsby addition of water to produce a polymer; {circle over (2)} the polymeris dissolved in an organic solvent to form a spinning liquid; {circleover (3)} the spinning liquid is spun to form precursor fibers; {circleover (4)} the precursor fibers are treated with steam before and/orduring calcination. According to this method, a silicon compound isadded in such an amount in the step {circle over (1)} or {circle over(2)} as to adjust the silica content preferably to 5-30 wt % and oneexample gives the results that the contents of silica and V₂O₅ arerespectively 12 wt % and 19 wt % and the fibrous titanium oxide catalystobtained after 1-hour calcination in air at 500° C. shows a specificsurface area of 173 m²/g.

[0016] A method for preparing an alumina-titanium oxide compositecatalyst carrier is disclosed in JP5-184,921 A comprises adding atitanium hydroxycarboxylate and/or a sol of titanium oxide and hydroxideand a hydroxycarboxylic acid to oxide and/or hydroxide of aluminum sothat the molar ratio of titanium oxide to alumina becomes 2.0 or lessand the molar ratio of the hydroxycarboxylic acid to the aforementionedtitanium oxide becomes 0.2-2.0 and calcining the kneaded mixture. In oneexample, a catalyst carrier prepared by calcining at 600° C. for 2 hoursand showing a molar TiO₂/Al₂O₃ ratio of 1.53 and a molarhydroxycarboxylic acid/TiO₂ ratio of 1.0 shows a specific surface areaof 200 m²/g.

[0017] A method proposed in JP08-057,322 A for preparing aphosphorus-containing titanium oxide catalyst carrier compriseshydrolyzing a titanium salt to give a hydrated cake of titanium oxide,adding a specified amount of phosphorus to the cake, plasticizing themixture and molding and calcining in accordance with a specifiedprocedure to give a titanium oxide catalyst carrier containing 1-5 wt %of phosphorus computed as oxide. In an example, a titanium oxidecatalyst carrier obtained by 2-hour calcination at 500° C. shows aspecific surface area of 108 m²/g.

[0018] A method proposed in JP07-232,075 A for preparing a catalyst forremoval of nitrogen oxide comprises mixing an oxide or hydrated oxide oftitanium and phosphorus so that phosphorus accounts for 0.1-6 wt % oftitanium oxide in the mixture, calcining the mixture at 450-800° C. andapplying vanadium to the calcined product. In an example, titanium oxideprepared by 2-hour calcination at 550° C. and containing 2.5 wt % ofphosphorus relative to titanium oxide shows a specific surface area of125 m²/g before application of vanadium.

[0019] Although the aforementioned technique involving addition of asecondary component such as silica, alumina and phosphorus to titaniumoxide can help to improve heat stability and give porous titanium oxidethat is capable of maintaining a large surface area even after a hightemperature heat treatment, the technique in question is not capable ofcontrolling the pore size and pore distribution of porous titanium oxidesharply and the scarcity of pore sizes optimal for the reaction in thecatalyst has made it difficult to obtain sufficient performance inrespect to such factors as reaction selectivity, activity and catalystlife.

[0020] It is important that catalyst carriers and catalysts used in avariety of chemical reactions have not only a large specific surfacearea and good heat stability but also a precisely controlled porestructure in respect to pore size and pore distribution. Generally, itis important that molecules taking part in a chemical reaction diffusereadily to the active sites of a catalyst to achieve good contact andreadily come off the active sites upon completion of the reaction. Forthis purpose, it is important that the pore size is controlled to suitthe target reactants. That is to say, it is important that catalystsoffer no resistance to the diffusion of the reactants and, in addition,they are devoid of too small pores which are not effective for thereaction or too large pores which are wasteful. An ideal catalyst is theone that has pores controlled to fit the aim of the reaction. Forexample, the effective pore diameter of a catalyst varies from reactionto reaction and it is 6-10 nm for hydrodesulfurization of gas oil, 8-15nm for hydrodesulfurization of heavy oil, 15-30 nm forhydrodemetallization and 20-40 nm for asphaltene removal.

[0021] From the aforementioned point of view, attempts such as thefollowing have been made to prepare porous titanium oxide having acontrolled pore structure in respect to pore diameter, pore distributionand the like.

[0022] A method proposed in JP60-50,721 B for preparing porous inorganicoxides comprises a step in which a hydrosol to serve as a seed isobtained, a step in which the pH of the hydrosol is swung between thehydrosol-dissolving range and the hydrosol-precipitating range (pH swingoperation) thereby causing growth of crystals and coarsely agglomeratingthe hydrosol and a step in which the coarse agglomerate of the hydrosolis dried and calcined to give a metal oxide. This method can surelyyield titanium oxide with a sharply controlled pore distribution;however, it was difficult by this method alone to prepare a titaniumoxide catalyst which shows no decrease in specific surface area nor lossof activity as a result of heat history involving heat applied tocalcination in the catalyst preparation and reaction heat evolved in thereaction system.

[0023] A method proposed in JP06-340,421 A for preparing porous titaniumoxide consists of adding ammonia water to a hydrolyzable titaniumcompound, for example, titanium tetrachloride, to form hydrated titaniumoxide, adding a polybasic carboxylic acid to the hydrated titanium oxideto form a chelate, shifting the pH from acidic to neutral by an alkalito separate an organic titanium oxide compound, deflocculating theresulting organic titanium oxide compound with an inorganic acid andfurther calcining the deflocculated product to give porous titaniumoxide. There is a description in an example that porous titanium oxideobtained by 24-hour calcination at 300° C. shows a total pore volume of0.348 ml/g, a BET specific surface area of 112 m²/g and a pore radius inthe range of 20-500 Å, mainly in the range of 32-120 Å with the mainpeak appearing at 120 Å, and it has a larger surface area and a lessbroad pore distribution than commercially available titanium oxide.However, this method has limited the calcining temperature to a lowlevel of 300° C. in order to maintain a high specific surface area and,besides, the main pores exist in a broad range of 32-120 Å as expressedin pore radius.

[0024] A method proposed in JP11-322,338 A for preparing porous titaniumoxide with a well-controlled fine structure consists of preparing atitanium-metal composite compound by adding to a solution of a titaniumalkoxide in a watermiscible organic solvent one kind or two kinds ormore of salts formed by neutralization of a weak acid with a weak base,a weak acid with a strong base or a weak base with a strong acid, water,and one kind or two kinds or more of salts of rare earth metals, andthen removing the metal from the composite compound by an acidtreatment, if necessary in the presence of a hydrolysis inhibitor. Thereis a description in an example that porous titanium oxide obtained after2-hour calcination at 600° C. shows a specific surface area of 90 m²/gor more but a broad pore distribution in the range of 100-600 Å.

[0025] Moreover, in the case where porous titanium oxide is used as acatalyst, it is necessary for titanium oxide to have high purity forfull manifestation of its catalytic properties.

[0026] According to Togari et al. [Togari, O., Ono, T. and Nakamura, M;Sekiyu Gakkaishi 22, (6), 336 (1979)], a catalyst carrier that is acomposite compound of Al₂O₃.TiO₂ or SiO₂.TiO₂ shows an increasinglygreater acid strength as the content of Al₂O₃ or SiO₂ increases.Further, as described in JP08-57,322 A, strong acid sites develop as thecontent of phosphorus in titanium oxide increases. Consequently, strongacid sites on the catalyst facilitate formation of coke and deactivationof the catalyst in the hydrodesulfurization of petroleum fractions and,according to the studies conducted by the inventors of this invention,the purity of titanium oxide on the oxide (TiO₂) basis is 97 wt % ormore, preferably 98 wt % or more, in order to maintain a highdesulfurization activity per unit specific surface area which ischaracteristic of titanium oxide and to suppress formation of coke.

[0027] By the way, sulfur components and nitrogen components containedin hydrocarbon oils derived from petroleum or coal are converted tosulfur oxides and nitrogen oxides when the hydrocarbon oils are burnedas fuel. They cause air pollution when discharged into air or they actas catalyst poisons when formed in the decomposition or conversionreactions of the hydrocarbon oils thereby lowering the efficiency ofthese reactions. Furthermore, sulfur components in fuel oils fortransportation are also poisons for those catalysts which treat exhaustgases discharged from gasoline- and diesel-driven vehicles.

[0028] Under the circumstances, hydroprocessing has been practiced toremove sulfur components and nitrogen components from hydrocarbon oilsand a large number of hydrotreating catalysts useful for hydroprocessinghave been proposed, for example, such catalysts consist of metalspossessing catalytic activity for hydrotreating such as molybdenum (Mo),tungsten (W), cobalt (Co) and nickel (Ni) and catalyst carriers such asalumina, zeolite-alumina, alumina-titanium oxide andphosphorus-silica-alumina as disclosed in JP6-106,061 A, JP9-155,197 A,JP9-164,334 A, JP2000-79,343 A, JP2000-93,804A, JP2000-117,111 A,JP2000-135,437 A and JP2001-62,304A.

[0029] Generally, a catalyst consisting of molybdenum and cobaltsupported on a catalyst carrier is mainly used where the removal ofsulfur components (desulfurization) from hydrocarbon oils is the majorobjective while a catalyst consisting of molybdenum or tungsten andnickel supported on a catalyst carrier is mainly used where thedesulfurization and additionally the removal of nitrogen(denitrogenation) are the objectives. The use of nickel here is said tobe due to its high capability of hydrogenating aromatic compounds.

[0030] The greater part of nitrogen components in hydrocarbon oilsoccurs as aromatic compounds and, when the removal of thenitrogen-containing aromatic compounds is effected by hydroprocessing,the hydrogenation of the aromatic rings takes place and the rupture ofC—N bonds ensues. Thus, the denitrogenation reaction progresses viaelimination of nitrogen as ammonia. For this reason, an enhancedcapability of hydrogenating aromatic compounds is required in thedenitrogenation reaction. As a results, there rises a problem of anincreased consumption of hydrogen when hydrocarbon oils are hydrorefinedin the presence of a hydrotreating catalyst containing nickel.

[0031] The 4th Report of the Central Environmental Council of theMinistry of the Environment, Japan, entitled “What the countermeasuresshould be for reduction of automobile exhaust gases in the future”presented in November, 2000 states that it is appropriate to reduce thesulfur components in gas oil or fuel oil for diesel engines from thecurrent level of 500 ppm to 50 ppm by the fiscal year 2004 and a stillfurther reduction of sulfur components is desirable in the future. Asfor the nitrogen components in hydrocarbon oils such as gas oil, theynot only deteriorate the quality of product oil by coloration but alsopoison and deteriorate hydrotreating catalysts during hydroprocessingand they should desirably be removed as much as possible.

[0032] However, hydroprocessing by the use of the aforementionedconventional hydrotreating catalysts does not necessarily givesufficient performance in desulfurization and denitrogenation and itbecomes necessary to conduct hydroprocessing under severer conditions inorder to reduce the sulfur components in gas oil to 50 ppm or less. Forexample, it would be necessary to reduce the throughput to ⅓ or toroughly treble the amount of the catalyst. Reduced throughput would callfor a critical review of the production schedule of an oil refinerywhile an increase in the amount of catalyst would require additionalinstallation of, say, two reactors. Or, it would be necessary to raisethe reaction temperature by 20° C. or more and this would be done at agreat sacrifice of the catalyst life. These measures would forciblyincur a great deal of economic burden. Moreover, it is difficult toremove nitrogen components by hydroprocessing to the same extent as inthe case of sulfur components and any attempt to effect hydroprocessingto remove nitrogen components at a high rate would require excessiveconsumption of hydrogen and this would necessitate installation of a newapparatus for producing hydrogen at an oil refinery where excesshydrogen is barely available.

[0033] As described above, it is not possible to prepare adesulfurization catalyst of high activity and this is for the followingreason: in a hydrotreating catalyst consisting of the principal catalystcomponent molybdenum and the promoter component cobalt and a catalystcarrier mainly composed of alumina, the amount of molybdenum is normally25 wt % or less on the oxide basis and any attempt to increasemolybdenum any further would cause agglomeration of molybdenum on thecatalyst carrier and this would prevent molybdenum from undergoing highdispersion and effectively manifesting catalytic performance and wouldadditionally produce such adverse effects as blocking pores anddecreasing surface area and pore volume thereby failing to exhibit aneeded activity.

DISCLOSURE OF THE INVENTION

[0034] The inventors of this invention have conducted extensive studieson porous 4 group metal oxides of excellent heat stability, a largespecific surface area and a high dispersion of a catalyst metal come tothe following finding and completed this invention; adding a particlegrowth inhibiter to a hydrosol a hydrogel or a dried product of ahydrous 4 group metal oxide represented by the general formulaMO_((2-x)) (OH)_(2x) (wherein M denotes a 4 group metal and x is anumber greater than 0.1 or x>0.1) followed by drying and calcining givesa porous 4 group metal oxide which has a specific surface area of 80m²/g or more, a pore volume of 0.2 ml/g or more and a pore sharpnessdegree of 50% or more, shows excellent heat stability and contains ahighly dispersed catalyst metal and, moreover, application of a pH swingoperation can produce a porous 4 group metal oxide which has acontrolled and sharp pore distribution and is useful as a catalyst or acatalyst carrier of excellent reaction selectivity.

[0035] Further, the inventors of this invention have found that addingone kind or two kinds of more of compounds that yield ions containing anelement selected from silicon (Si), phosphorus (P), magnesium (Mg),calcium (Ca), barium (Ba), manganese (Mn), aluminum (Al) and zirconium(Zr) in a very small amount as a particle growth inhibiter to ahydrosol, a hydrogel or a dried product of a hydrous 4 group metal oxiderepresented by the general formula MO_((2-x))(OH)_(2x) (wherein Mdenotes a 4 group metal and x is a number greater than 0.1 or x>0.1)followed by drying and calcining gives porous titanium oxide which has alarge specific surface area of 80 m²/g or more even when calcined at500° C. for 3 hours, exhibits excellent heat stability, has controlledpore size and shows a purity as high as 97 wt % or more and completedthis invention. That is, an ion exchange takes place between thethermally readily detachable hydroxyl ions of hydrous titanium oxideparticles whose pore diameter is precisely controlled and thermallydifficultly detachable polyvalent ions of the aforementioned elementsand, further, the polyvalent ions of the aforementioned elements whichhave undergone an ion exchange can produce, because of their stericeffect, an effect for preventing the nearby hydroxyl groups fromdetaching themselves and participating in condensation polymerization;this can effectively suppress or prevent the hydroxyl groups from comingoff the hydrous titanium oxide particles and the particles from growingfurther and completed this invention.

[0036] Further the inventors of this invention have found thatsynthesizing hydrous titanium oxide which is controlled to have sharppore distribution and, at the same time, further controlled to containmicropores in a specified range to make the pore distribution asymmetricfollowed by drying and calcining gives porous titanium oxide which iscontrolled to have an arbitrary pore diameter, has a pore distributionin a shape conforming to the molecular weight distribution of thereactants, has a larger specific surface area than porous titanium oxidewhich is controlled to have a uniform particle diameter and exhibitshigh mechanical strength and completed this invention.

[0037] Still further, the inventors of this invention have found thatthe aforementioned porous 4 group metal oxide, in particular, poroustitanium oxide, when prepared by adding two kinds or more of compoundsthat yield ions containing elements possessing catalytic activity forhydrotreating, preferably two kinds or more of compounds that yield ionscontaining elements constituting the principal catalyst component andpromoter component, as a particle growth inhibiter to a hydrosol ahydrogel or a dried product of hydrous titanium oxide represented by thegeneral formula MO_((2-x))(OH)_(2x) (wherein M denotes a 4 group metaland x is a number greater than 0.1 or x>0.1), the composition formulaTiO_((2-x))(OH)_(2x).yH₂O (wherein 0.1≦x<2.0 and 0.3≦=y≦40) or thecomposition formula TiO_((2-x)) (OH)_(2x).yH₂O (wherein 0.2≦x<1.0 and0.3≦y≦40) followed by drying and calcining, is useful as a hydrotreatingcatalyst for hydrocarbon oils, performing excellently not only indesulfurization but also in denitrogenation and achieving reduction ofsulfur and nitrogen contents on a commercial scale without requiringexcessive consumption of hydrogen and completed this invention.

[0038] Accordingly, an object of this invention is to provide a porous 4group metal oxide which shows excellent heat stability, has a largespecific surface area and contains a high dispersion of a catalyst metaland to provide a method for preparation thereof.

[0039] Another object of this invention is to provide a porous 4 groupmetal oxide which has a precisely controlled pore size and a sharp poredistribution in addition to excellent heat stability, a large specificsurface area and a high dispersion of a catalyst metal and is useful asa catalyst or a catalyst carrier of excellent reaction selectivity andto provide a method for preparation thereof.

[0040] A further object of this invention is to provide high-purityporous titanium oxide which has a large specific surface area, showsexcellent heat stability and has pores precisely controlled in size anddistributed sharply and to provide a method for preparation thereof.Precise control of pore size also means uniform and precise control ofthe diameter of titanium oxide particles.

[0041] A further object of this invention is to provide porous titaniumoxide which is controlled to have an arbitrary pore diameter, has a poredistribution in a shape conforming to the molecular weight distributionof the reactants, has a larger specific surface area than poroustitanium oxide that is controlled to have a uniform pore diameter andshows high mechanical strength.

[0042] A further object of this invention is to provide a hydrotreatingcatalyst for hydrocarbon oils which performs excellently indesulfurization and denitrogenation and requires minimal consumption ofhydrogen.

[0043] A further object of this invention is to provide a hydrotreatingcatalyst for hydrocarbon oils which performs excellently not only indesulfurization but also in denitrogenation and can advantageouslyachieve reduction of sulfur and nitrogen components on a commercialscale while avoiding excessive consumption of hydrogen in the course ofhydroprocessing and to provide a method for preparation thereof.

[0044] A further object of this invention is to provide ahydroprocessing method which makes use of a hydrotreating catalyst forhydrocarbon oils possessing excellent activity for both desulfurizationand denitrogenation and consuming a not too excessive amount of hydrogenand accomplishes a high degree of removal of both sulfur and nitrogencomponents from hydrocarbon oils.

[0045] Accordingly, this invention relates to a 4 group metal oxideobtained by adding a particle growth inhibiter to a hydrosol a hydrogelor a dried product of a hydrous 4 group metal oxide represented by thegeneral formula MO_((2-x))(OH)_(2x) (wherein M denotes a 4 group metaland x is a number greater than 0.1 or x>0.1), followed by drying andcalcining and the product occurs as a porous 4 group metal oxide havinga specific surface area of 80 m²/g or more, a pore volume of 0.2 ml/g ormore and a pore sharpness degree of 50% or more. Of the aforementionedhydrous 4 group metal oxides represented by the general formulaMO_((2-x))(OH)_(2x), a preferred case is where the 4 group metal M istitanium (Ti) and the hydrous 4 group metal oxide in question is hydroustitanium oxide and, still more, the hydrous titanium oxide isrepresented either by the composition formula TiO_((2-x))(OH)_(2x).yH₂O(wherein 0.1≦x<2.0 and 0.3≦y≦40) or by the composition formulaTiO_((2-x))(OH)_(2x).yH₂O (wherein 0.2≦x<1.0 and 0.3≦y≦40).

[0046] Further, this invention relates to a method for preparing porous4 group metal oxide which comprises adding a particle growth inhibiterto a hydrosol a hydrogel or a dried product of a hydrous 4 group metaloxide obtained by the reaction of a 4 group metal compound as a rawmaterial with a pH adjusting agent in an aqueous solvent and representedby the general formula MO_((2-x))(OH)_(2x) (wherein M denotes a 4 groupmetal and x is a number greater than 0.1 or x>0.1) followed by dryingand calcining. Of the aforementioned hydrous 4 group metal oxidesrepresented by the general formula MO_((2-x))(OH)_(2x), a preferred caseis where the 4 group metal M is titanium (Ti) and the hydrous 4 groupmetal oxide in question is hydrous titanium oxide and, still more, thehydrous titanium oxide is represented either by the composition formulaTiO_((2-x))(OH)_(2x).yH₂O (wherein 0.1≦x<2.0 and 0.3≦y≦40) or by thecomposition formula TiO_((2-x))(OH)_(2x).yH₂O (wherein 0.2≦x<1.0 and0.3≦y≦40).

[0047] Further, this invention relates to a hydrotreating catalyst forhydrocarbon oils comprising a porous 4 group metal oxide obtained by theuse of a compound that yields ions containing an element having acatalytic activity for hydrotreating as a particle growth inhibiter.Particularly preferable here is a hydrotreating catalyst for hydrocarbonoils in which the 4 group metal M is titanium (Ti).

[0048] Still further, this invention relates to a method forhydroprocessing hydrocarbon oils which comprises bringing hydrocarbonoils into contact with the aforementioned hydrotreating catalyst in thepresence of hydrogen under the hydrotreating conditions of a reactiontemperature of 280-400° C., a reaction pressure of 2-15 MPa, an LISV of0.3-10 hr⁻¹ and a hydrogen/oil ratio of 50-500 Nl/l for removal ofsulfur and nitrogen components from the hydrocarbon oils.

[0049] Depending upon the mode of practice, this invention can typicallybe described in the following manner.

[0050] Firstly, this invention relates to a porous 4 group metal oxidewhich is obtained by adding a particle growth inhibiter to a hydrosol ahydrogel or a dried product of a hydrous 4 group metal oxide representedby the general formula MO_((2-x))(OH)_(2x) (wherein M denotes a 4 groupmetal and x is a number greater than 0.1 or x>0.1) following by dryingand calcining, has a specific surface area of 80 m²/g or more, a porevolume of 0.2 ml/g or more and a pore sharpness degree of 50% or more,shows excellent heat stability, has a high dispersion of a catalystmetal and is useful as a catalyst or a catalyst carrier. Further, thisinvention relates to a porous 4 group metal oxide which is obtained byapplication of a pH swing operation, has a large specific surface area,shows excellent heat stability, has a high dispersion of a catalystmetal and a controlled and sharp pore distribution and is useful as acatalyst or a catalyst carrier of excellent reaction selectivity and toa method for preparation thereof.

[0051] Secondly, this invention relates to porous titanium oxide whichis obtained by adding one kind or two kinds or more of compounds thatyield ions containing elements selected from silicon (Si), phosphorus(P), magnesium (Mg), calcium (Ca), barium (Ba), manganese (Mn), aluminum(Al) and zirconium (Zr) in a very small amount as a particle growthinhibiter to a hydrosol, a hydrogel or a dried product of hydroustitanium oxide represented by the general formula TiO_((2-x))(OH)_(2x)(wherein x is a number greater than 0.1 or x>0.1) following by dryingand calcining, is characterized by a large surface area, excellent heatstability and controlled pore diameter as proved by having a specificsurface area of 80 m²/g or more, a pore volume of 0.2 ml/g or more and apore sharpness degree of 50% or more even when calcined at 500° C. for 3hours, shows a purity of 97 wt % or more and is useful as a catalyst ora catalyst carrier and to a method for preparation thereof.

[0052] Thirdly, this invention relates to porous titanium oxide which isobtained by synthesizing hydrous titanium oxide which is controlled tohave a sharp pore distribution and, at the same time, controlled tocontain micropores in a specified range to make the pore distributionasymmetric followed by drying and calcining, has a pore asymmetriccoefficient N in the range of 1.5≦N≦4 as defined by the equationN=(A−C)/(B−A) (wherein A is the logarithmic value of the mediandiameter, B is the logarithmic value of the pore diameter of the 2% porevolume and C is the logarithmic value of the pore diameter of the 98%pore volume), is controlled to have an arbitrary pore diameter and apore distribution in a shape conforming to the molecular weightdistribution of the reactants, has a larger specific surface area thanporous titanium oxide which is controlled to have a uniform particlediameter and shows good mechanical strength and to a method forpreparing such porous titanium oxide; the method involves a pH swingoperation during the synthesis of hydrous titanium oxide and the pHswing operation is performed in the non-dissolving pH range of hydroustitanium oxide between the range on the low pH side (1<pH≦4) and the pHrange near the isoelectric point of hydrous titanium oxide (5.1≦pH≦7.1)or between the pH range near the isoelectric point of hydrous titaniumoxide (5.1≦pH≦7.1) and the range on the high pH side (8≦pH≦12) accordingto one mode of practice or the pH swing operation is performed in thenon-dissolving pH range of hydrous titanium oxide between the range onthe low pH side (1<pH≦4) and the range across the pH range near theisoelectric point of hydrous titanium oxide (5.1≦pH≦7.1) or between therange on the high pH side (8≦pH≦12) and the range across the pH rangenear the isoelectric point of hydrous titanium oxide (5.1≦pH≦7.1) whileallowing a sufficient aging time for growth of particles in the pH rangenear the isoelectric point of hydrous titanium oxide (5.1≦pH≦7.1)according to another mode of practice.

[0053] Fourthly, this invention relates to a hydrotreating catalystwhich is a catalyst supported on titanium oxide obtained by adding atleast two kinds or more of compounds selected from compounds yieldingions containing elements possessing catalytic activity forhydrotreating, preferably two kinds or more of compounds constitutingthe principal catalyst component and promoter component, as a particlegrowth inhibiter to a hydrosol a hydrogel or a dried product of hydroustitanium oxide represented by the general formula TiO_((2-x))(OH)_(2x)is a number greater than 0.1 or x>0.1), the composition formulaTiO_((2-x))(OH)_(2x).yH₂O (wherein 0.1≦x<2.0 and 0.3≦y≦40) or thecomposition formula TiO_((2-x))(OH)_(2x).yH₂O (wherein 0.2≦x<1.0 and0.3≦y≦40) thereby exchanging the hydroxyl groups of the hydrous titaniumoxide with the ions of these elements followed by drying and calciningand has a specific surface area of 80 m²/g or more, a pore volume of 0.2ml/g or more and a pore sharpness degree of 50% or more, shows excellentdesulfurization and denitrogenation performance and acts as ahydrotreating catalyst for hydrocarbon oils with minimal consumption ofhydrogen and to a method for preparation thereof. Furthermore, thisinvention relates to a method for hydroprocessing hydrocarbon oils bythe use of the aforementioned catalyst.

[0054] Here, hydrous titanium oxide represented by the general formulaTiO_((2-x))(OH)_(2x) or the composition formulaTiO_((2-x))(OH)_(2x).yH₂O can be divided into the portion of structuralwater chemically bonded to hydrous titanium oxide written asTiO_((2-x))(OH)_(2x) and the portion of free water physically coexistingwith hydrous titanium oxide written as yH₂O. In this invention, theamount of structural water is defined as the change in weight betweendrying and calcining when hydrous titanium oxide is dried at 120° C. for3 hours and then further calcined at 500° C. for 3 hours. On the otherhand, the amount of free water written as yH₂O is defined as the changein weight between undried hydrous titanium oxide and dried titaniumoxide.

[0055] In a hydrosol a hydrogel or a dried product of a hydrous 4 groupmetal oxide represented by the general formula MO_((2-x))(OH)_(2x)(wherein M denotes a 4 group metal and x is a number greater than 0.1 orx>0.1) in this invention, “x>0.1” means that the lower limit of the OHgroups possessed by a hydrosol a hydrogel or a dried product of ahydrous 4 group metal oxide exceeds 0.1, but preferably 0.1≦x<2.0, morepreferably 0.2≦x<1.0. Growth of particles occurs by sintering andcondensation as the OH groups detach themselves from a hydrosol, ahydrogel or a dried product of a hydrous 4 group metal oxide as a resultof heat history and replacement of the substitutable OH groups withother functional groups increases heat stability and the specificsurface area. In consequence, it is also possible to use a hydrous 4group metal oxide which is prepared by the methods generally used up tothe present such as hydrolysis, neutralization and sol-gel method.

[0056] A preferred hydrous 4 group metal oxide is the one in which the 4group metal M is titanium (Ti) and is represented preferably by thegeneral formula TiO_((2-x))(OH)_(2x) (wherein x is a number greater than0.1 or x>0.1), the composition formula TiO_((2-x))(OH)_(2x).yH₂O(wherein 0.1≦x<2.0 and 0.3≦y≦40) or the composition formulaTiO_((2-x))(OH)_(2x).yH₂O (wherein 0.2≦x<1.0 and 0.3≦y≦40). When thevalue of x in the aforementioned formulas is 0.1 or less, it becomesdifficult to obtain a large specific surface area because of the growthof hydrous titanium oxide crystals and to attain a high dispersion ofthe catalyst components uniformly in high concentration because of thedecrease in the hydroxyl groups on the surface of hydrous titanium oxideion-exchangeable with the catalyst components. Conversely, when x is 2.0or more, the crystals of hydrous titanium oxide do not form which makesit impossible to obtain a hydrosol or a hydrogel of hydrous titaniumoxide in some cases; although the presence of a large number of hydroxylgroups ion-exchangeable with the catalyst components is desirable fromthe viewpoint of supporting the catalyst components on a catalystcarrier, the crystal particles of hydrous titanium oxide are small andamorphous when examined by X-ray and the catalyst obtained after dryingand calcining has an inadequate pore structure or an inferior quality asa hydrotreating catalyst in other cases. When y is less than 0.3 in theaforementioned formulas, hydrous titanium oxide is in the nearly drycondition and it is difficult to obtain a uniform and high dispersion ofthe catalyst components under such condition; moreover, when a solutioncontaining the catalyst components is added to hydrous titanium oxideparticles and stirred, the dispersion of the catalyst componentsprogresses with difficulty because of agglomeration of the hydroustitanium oxide particles and it is difficult to obtain a uniform andhigh dispersion in this case. As a result, a uniform and high dispersionis not possible to attain when the catalyst components need to besupported on titanium oxide in high concentration and the catalystcomponents form an agglomerate or a lump with the resultant lowcatalytic activity. Conversely, when y is in excess of 40, the amount offree water that is not structural water of hydrous titanium oxidebecomes excessive and hydrous titanium oxide cannot be molded or, evenif molded, the molded form becomes difficult to maintain. A solutioncontaining the catalyst components becomes diluted when added to hydroustitanium oxide containing excessive free water and the catalystcomponents mostly do not undergo ion exchange and are wasted.

[0057] The raw materials 4 group metal compounds useful for thepreparation of a hydrosol a hydrogel or a dried product of a hydrous 4group metal oxide include the following: chlorides, fluorides, bromides,iodides, nitrates, sulfates, carbonates, acetates, phosphates, borates,oxalates, hydrofluoric acid salts, silicates and iodates of 4 groupmetals such as titanium (Ti), zirconium (Zr) and hafnium (Hf); oxoacidsalts such as titanates, zirconates and hafnates of 4 group metals; andalkoxides of 4 group metals. Of these compounds of 4 group metals,particularly preferable in the case of titanium (Ti) compounds aretitanium tetrachloride, titanium sulfate, titanyl sulfate, titaniumtrichloride, titanium methoxide, titanium ethoxide, titanium propoxide,titanium isopropoxide, titanium tetraisopropoxide, titaniumtetrabutoxide, orthotitanic acid, metatitanic acid, titaniumtetrabromide, titanium tetrafluoride, titanium trifluoride, potassiumtitanate, sodium titanate and barium titanate. Likewise, particularlypreferable in the case of zirconium (Zr) compounds are zirconiumtetrachloride, zirconium oxychloride, zirconium sulfate, zirconiumnitrate, zirconium acetate, zirconium acetylacetate, zirconium propoxideand zirconium t-butoxide. Particularly preferable in the case of hafniumcompounds are hafnium chloride, hafnium sulfate and hafnium oxychloride.These raw materials 4 group metal compounds may be used singly or as amixture of two kinds or more.

[0058] The pH adjusting agents to be used in the synthesis of theaforementioned hydrous 4 group metal oxides include the salts of thecorresponding 4 group metals such as chlorides, fluorides, bromides,iodides, nitrates, sulfates, carbonates, acetates, phosphates, borates,oxalates, hydrofluoric acid salts, silicates and iodates and alsoinclude those compounds (salts) which are added as a particle growthinhibiter to be explained below and a variety of acids and alkalis.

[0059] Concrete examples of titanium salts suitable for use as a pHadjusting agent in the synthesis of hydrous titanium oxide are titaniumtetrachloride, titanium sulfate, titanyl sulfate, titanium trichloride,titanium tetrabromide, titanium tetrafluoride and titanium trifluoride.Examples of the compounds (salts) to be added as a particle growthinhibiter are ferrous sulfate, ferric sulfate, ferrous chloride, ferricchloride, ferrous nitrate, ferric nitrate, nickel nitrate, nickelsulfate, nickel chloride, cobalt nitrate, cobalt sulfate, cobaltchloride, manganese nitrate, manganese sulfate, manganese chloride,yttrium nitrate, yttrium sulfate and yttrium chloride. Examples of theacids are nitric acid (HNO₃), hydrochloric acid (HCl), sulfuric acid(H₂SO₄), carbonic add (H₂CO₃), formic add (HCOOH) and acetic add(CH₃COOH). Examples of the alkalis are ammonia (NH₃), sodium hydroxide(NaOH), potassium hydroxide (KOH), sodium carbonate (Na₂CO₃), potassiumcarbonate (K₂CO₃), sodium hydrogencarbonate (NaHCO₃) and potassiumhydrogencarbonate (KHCO₃). These pH adjusting agents may be used singlyor as a mixture of two kinds or more.

[0060] The aqueous solvents to be used in the synthesis of hydrous 4group metal oxides is not restricted and water and aqueous solutions ofwatersoluble organic solvents such as methanol ethanol propanoltetrahydrofuran, acetone and dioxane may be used.

[0061] A hydrosol a hydrogel or a dried product of the aforementionedhydrous 4 group metal oxides can be synthesized by the reaction of oneof the aforementioned raw materials 4 group metal compounds with a pHadjusting agent in an aqueous solvent. For example, hydrous titaniumoxide is synthesized by hydrolyzing a titanium compound selected fromthe aforementioned raw materials by an acid or alkali selected from theaforementioned pH adjusting agents or neutralized by an alkali in anaqueous solvent.

[0062] In the hydrolysis or alkali neutralization of a raw materialtitanium compound, the concentration of titanium in the aqueous solventis normally 0.1-15 wt %, preferably 0.5-10 wt %, more preferably 0.5-6wt %, computed as titanium oxide (TiO₂), the reaction temperature rangesfrom room temperature to 300° C., preferably from room temperature to180° C., more preferably from room temperature to 100° C., the reactionpressure ranges from normal pressure (0 MPa) to 9.0 MPa, preferably from0 to 3.0 MPa, more preferably from 0 to 0.9 MPa, and the pH is selectedsuitably in order to control the pore structure to have it adapted tothe object to which titanium oxide is used.

[0063] In this invention, in order to obtain a porous 4 group metaloxide which has a controlled pore structure in respect to pore diameter,pore distribution and the like, a pH swing operation is performedbetween the ranges of different pH plural times in an aqueous solvent bythe use of a 4 group metal compound as a raw material and a pH adjustingagent in the synthesis of a hydrosol a hydrogel or a dried product ofthe aforementioned hydrous 4 group metal oxide.

[0064] In particular, the aforementioned pH swing operation is performedpreferably between the precipitating pH range and the dissolving pHrange of the hydrous 4 group metal oxide in order to obtain porous 4group metal oxide in which the pores are precisely controlled in sizeand distributed sharply. For example, in the synthesis of a hydrosol ora hydrogel of hydrous titanium oxide, the pH is swung alternatelybetween the precipitating pH range and the dissolving pH range ofhydrous titanium oxide shown in the electrochemical potential diagram oftitanium oxide [M. Pourbaix, “Atlas of Electrochemical Equilibria inAqueous Solution,” Pergamon Press, London (1966)] plural times, normally2-20 times, and the pore structure involving such factors as porediameter and pore distribution of the hydrous titanium oxide particlesbeing synthesized can be controlled increasingly more precisely byregulating the pH in the precipitating range, the pH in the dissolvingrange and the number of swings. For example, the peak of pore diameterappears at 8.2 nm in the pore distribution when the pH swing operationis performed twice between pH 1 and pH 7 while the peak appears at 16.1nm when the pH swing operation is performed four times between pH 1 andpH 7; thus it is possible to prepare porous titanium oxide with astrictly controlled pore structure.

[0065] In the case where high mechanical strength is required for aporous 4 group metal oxide in which the 4 group metal M is titanium(Ti), it is preferable to perform the aforementioned pH swing operationas follows: {circle over (1)} the operation is performed in the range ofthe non-dissolving pH range of hydrous titanium oxide (1<pH≦12) in theelectrochemical potential diagram of titanium oxide between the range onthe low pH side (1<pH≦4) and the pH range near the isoelectric point ofhydrous titanium oxide (5.1≦pH≦7.1) or between the pH range near theisoelectric point (5.1≦pH≦7.1) and the range on the high pH side(8≦pH≦12); {circle over (2)} the operation is performed in thenon-dissolving pH range (1<pH≦12) between the range on the low pH side(1<pH≦4) and the range across the pH range near the isoelectric point(5.1≦pH≦7.1) or between the range on the high pH side (8≦pH≦12) and therange across the pH range near the isoelectric point (5.1≦pH≦7.1) whileallowing a sufficient aging time for growth of particles. This procedureis suitable for the preparation of porous titanium oxide whose poreasymmetric coefficient N defined by N=(A−C)/(B−A) (wherein A is thelogarithmic value of the median diameter, B is the logarithmic value ofthe pore diameter of the 2% pore volume and C is the logarithmic valueof the pore diameter of the 98% pore volume) falls in the range of1.5≦N≦4.

[0066] In this invention, a particle growth inhibiter is added to ahydrosol a hydrogel or a dried product of a hydrous 4 group metal oxidesynthesized in the aforementioned manner and the mixture is dried andcalcined to give a porous 4 group metal oxide.

[0067] Addition of a particle growth inhibiter to a hydrosol a hydrogelor a dried product of hydrous titanium oxide represented by the generalformula TiO_((2-x))(OH)_(2x) (wherein x is a number greater than 0.1 orx>0.1) followed by drying and calcining gives porous titanium oxidewhich has a large specific surface area and shows excellent heatstability as proved by having a specific surface area of 80 m²/g ormore, a pore volume of 0.2 ml/g or more and a pore sharpness degree of50% or more even when calcined at a temperature as high as 500° C. for 3hours, has a controlled pore diameter, exhibits a high purity of 97 wt %or more and is useful for a catalyst or a catalyst carrier; particlegrowth inhibiters suitable for the preparation of the aforementionedporous titanium oxide are compounds that yield ions containing elementsselected from silicon (Si), phosphorus (P), magnesium (Mg), calcium(Ca), barium (Ba), manganese (Mn), aluminum (Al) and zirconium (Zr) andthese compounds may be used singly or as a mixture of two kinds or more.Importantly, any compound which is added as a particle growth inhibiterto a hydrous 4 group metal oxide, particularly, to hydrous titaniumoxide, is required to be effective for maintaining the specific surfacearea of hydrous titanium oxide at a high level not to interfere with thecontrol of pore distribution of titanium oxide, not to become a catalystpoison by remaining as its oxide in porous titanium oxide and to beinexpensive from the economical point of view.

[0068] A plausible mechanism by which the compounds that yield ionscontaining the aforementioned elements act as a particle growthinhibiter against a hydrosol a hydrogel or a dried product of hydroustitanium oxide is as follows. Fine particles of hydrous titanium oxidebecome charged with electricity in an aqueous solution and theisoelectric point in the case of anatase crystals is near pH 6.1. In asolution whose pH is short of the isoelectric point, the hydroxyl groupson the surface of the hydrous titanium oxide particles are chargedpositively and anions in the solution readily adhere to the surface ofthe hydrous titanium oxide particles. On the other hand, in a solutionwhose pH exceeds the isoelectric point, the hydroxyl groups on thesurface of the hydrous titanium oxide particles are charged negativelyand cations in the solution readily adhere to the surface of the hydroustitanium oxide particles. In a case such as this, the anions or cationsin the solution disperse to a high degree on the surface of hydroustitanium oxide particles by the electrostatic action and bondeffectively and firmly to the hydroxyl groups on the surface even whentheir amounts are small relative to that of the hydroxyl groups. Forthis reason, when hydrous titanium oxide is calcined, the portions whichhave been ion-exchanged with anions or cations do not form the crystallattice (Ti—O—Ti) of hydrous titanium oxide because of the presence offirmly bonded anions or cations and this does not lead to crystalgrowth. Moreover, those hydroxyl groups which are near the portionsbonded to anions or cations are subject to the influence of sterichindrance of anions or cations and bond with difficulty to the hydroxylgroups on the surface of other hydrous titanium oxide particles.

[0069] From a point of view such as this, polyvalent anions or cationswhich suppress the growth of hydrous titanium oxide particles arecapable of bonding to more hydroxyl groups than monovalent anions orcations and they are more effective for interfering with the particlegrowth of hydrous titanium oxide in the steps for drying and calcining.Now, it is the aforementioned compounds of silicon (Si), phosphorus (P),magnesium (Mg), calcium (Ca), barium (Ba), manganese (Mn), aluminum (Al)and zirconium (Zr) that yield such polyvalent anions or cations and areuseful as a particle growth inhibiter of hydrous titanium oxide.

[0070] Concrete examples of the aforementioned compounds useful as aparticle growth inhibiter of hydrous titanium oxide are the following.The compounds of silicon (Si) are silicon tetrachloride, silicondioxide, silicic acid, silicate salts, silicic anhydride, molybdenumsilicate and silicate ions. The compounds of phosphorus (P) arephosphoric acid, phosphorous acid, metaphosphoric acid, pyrophosphoricacid, phosphorus oxide, ammonium phosphates, calcium phosphates,magnesium phosphates, barium phosphates, potassium phosphates and sodiumphosphates. The compounds of magnesium (Mg) are magnesium nitrate,magnesium sulfate, magnesium carbonate, magnesium borate, magnesiumacetate, magnesium oxide, magnesium hydroxide, magnesium fluoride,magnesium chloride, magnesium bromide, magnesium iodide, magnesiumcarbide, organic acids containing magnesium, magnesium, magnesium ionsand magnesium molybdate and the hydrates and the like of theaforementioned compounds.

[0071] The compounds of calcium (Ca) are calcium nitrate, calciumsulfate, calcium carbonate, calcium borate, calcium acetate, calciumoxide, calcium hydroxide, calcium fluoride, calcium chloride, calciumbromide, calcium iodide, calcium carbide, organic acids containingcalcium, calcium, calcium ions and calcium molybdate and the hydratesand the like of the aforementioned compounds. The compounds of barium(Ba) are barium nitrate, barium sulfate, barium carbonate, bariumborate, barium acetate, barium oxide, barium hydroxide, barium fluoride,barium chloride, barium bromide, barium iodide, barium carbide, organicacids containing barium, barium, barium ions and barium molybdate andthe hydrates and the like of the aforementioned compounds. The compoundsof manganese (Mn) are manganese nitrate, manganese sulfate, manganeseammonium sulfate, manganese carbonate, manganese borate, manganeseacetate, manganese oxide, manganese hydroxide, manganese fluoride,manganese chloride, manganese bromide, manganese iodide, manganesecarbide, organic acid containing manganese, manganese, permanganates andmanganese molybdate and the hydrates and the like of the aforementionedcompounds.

[0072] The compounds of aluminum (Al) are aluminum acetate, ammoniumaluminum sulfate, aluminum bromide, aluminum chloride, aluminumfluoride, aluminum hydroxide, aluminum lactate, aluminum nitrate,aluminum perchlorate, potassium aluminum sulfate, aluminum silicate,sodium aluminum sulfate, aluminum sulfate, aluminum trifluoride andaluminum and the hydrates and the like of the aforementioned compounds.The compounds of zirconium (Zr) are zirconium sulfate, sulfatedzirconia, zirconium carbide, zirconium tetrachloride, zirconiumoxychloride, zirconium hydride, zirconium tetraiodide, zirconium oxide,zirconium n-propoxide, zirconyl nitrate, zirconyl carbonate, zirconylhydroxide, zirconyl sulfate, zirconyl acetate and zirconium and thehydrates and the like of the aforementioned compounds.

[0073] A silicon or phosphorus compound to be added to hydrous titaniumoxide as a particle growth inhibiter is stable as oxide and produces abetter effect when present in the form of an oxyanion in the aqueoussolution. A silicon compound primarily appears to exist as SiO₃ ²⁻ inthe aqueous solution while a phosphorus compound as PO₄ ³⁻. Compounds ofmagnesium, calcium, barium, zirconium and manganese with a greaterionization tendency produce a greater effect when present in the form oftheir cations in the aqueous solution. The aforementioned compoundsacting as a particle growth inhibiter are likely to assume the form ofMg²⁺, Ca²⁺, Ba²⁺, Zr⁴⁺ or Mn²⁺. A compound of aluminum is relativelystable as a hydroxide Al₂O₃.xH₂O; moreover, as it can assume the form ofeither an anion or a cation, it is considered to be present as AlO₃ ³⁻in the case of an anion or as Al³⁺ in the case of a cation.

[0074] When a compound yielding ions of an element selected from silicon(Si), phosphorus (P), magnesium (Mg), calcium (Ca), barium (Ba),manganese (Mn), aluminum (Al) and zirconium (Zr) is added as a particlegrowth inhibiter to hydrous titanium oxide, its concentration is notrestricted in any specific way; however, where the preparation of poroustitanium oxide characterized by a large specific surface area, excellentheat stability, precisely controlled pore size, a sharp poredistribution and a high purity, preferably 97 wt % or more, is aimed at,it is necessary to add the compound in question, computed as its oxide,at a rate in the range of 0.1-3 wt %, preferably in the range of 0.2-2wt %, of hydrous titanium oxide. When the particle growth inhibiter thusadded to hydrous titanium oxide is less than 0.1 wt %, it does notmanifest the effect for increasing the specific surface area of titaniumoxide sufficiently Conversely, when the addition exceeds 3 wt %, poroustitanium oxide of high purity cannot be obtained and, besides, titaniumoxide itself does not increase in specific surface area to anyappreciable extent.

[0075] The method for adding the aforementioned particle growthinhibiter to a hydrous 4 group metal oxide, for example, hydroustitanium oxide, is not restricted: a particle growth inhibiter may beadded to the raw materials (for example, a 4 group metal compound, a pHadjusting agent, an aqueous solvent, etc.) during the preparation of ahydrosol or a hydrogel of hydrous titanium oxide; it may be added to thereaction solvent during synthesis; where a pH swing operation isperformed, it may be added to the raw materials 4 group metal compoundand pH adjusting agent to be used in the pH swing operation; or it maybe added in the step after synthesis and before dehydration.

[0076] In the case where hydrous titanium oxide is prepared byneutralizing the raw material titanium chloride with ammonia, impuritiessuch as chlorine and ammonia remain in the hydrosol or hydrogel of suchhydrous titanium oxide and these impurities need to be removed bywashing with water; washing water containing a given particle growthinhibiter may be used as washing water in the steps for filtration andwashing after the synthesis of the aforementioned hydrous titaniumoxide, thereby adding the particle growth inhibiter to hydrous titaniumoxide through the washing water or gel-like hydrous titanium oxide afterwashing may be mixed with the particle growth inhibiter. In this case,the concentration of the particle growth inhibiter in washing water ispreferably in the range of 1-100 ppm on the basis of the oxide of theelement in the particle growth inhibiter. Adoption of these methods cangreatly simplify the procedure for adding a particle growth inhibiter tohydrous titanium oxide. Furthermore, a particle growth inhibiter ofhydrous titanium oxide may be added to hydrous titanium oxide after adrying treatment.

[0077] When polyvalent anions are added as a particle growth inhibiterto hydrous titanium oxide, the pH of the sol or gel of hydrous titaniumoxide is preferably controlled at a point below the isoelectric point ofhydrous titanium oxide. On the other hand, when polyvalent cations areadded as a particle growth inhibiter to hydrous titanium oxide, the pHof the sol or gel of hydrous titanium oxide is preferably controlled ata point above the isoelectric point of hydrous titanium oxide. Moreover,when both polyvalent anions and polyvalent cations are added together asparticle growth inhibiters to hydrous titanium oxide, controlling the pHof the sol or gel of hydrous titanium oxide at the isoelectric point ofhydrous titanium oxide ±1.0 can cause the particle growth inhibiter toadhere effectively to the sol or gel.

[0078] In the case where a particle growth inhibiter is added to ahydrosol, a hydrogel or a dried product hydrous titanium oxiderepresented by the general formula TiO_((2-x))(OH)_(2x) (wherein x is anumber greater than 0.1 or x>0.1), the composition formulaTiO_((2-x))(OH)_(2x).yH₂O (wherein 0.1≦x<2.0 and 0.3≦y≦40) or thecomposition formula TiO_((2-x))(OH)_(2x).yH₂O (wherein 0.2≦x<1.0 and0.3≦y≦40) and the mixture is dried and calcined to give a catalystsupported on titanium oxide which has a specific surface area of 80m²/g, a pore volume of 0.2 ml/g or more and a pore sharpness degree of50% or more for use as a hydrotreating catalyst for hydrocarbon oils, acompound yielding ions of an element that shows catalytic activity forhydrotreating is added as the aforementioned particle growth inhibiterand the ions of the element in question undergo an ion exchange with thehydroxyl groups of hydrous titanium oxide.

[0079] The compounds to be used for the aforementioned purpose as aparticle growth inhibiter are required to be compounds that yield ionsof elements possessing catalytic activity for hydrotreating; thosecompounds which yield ions of the principal catalyst elements molybdenum(Mo) and/or tungsten (W) are indispensable and other compounds yieldingions of elements which act as promoters include compounds containingelements of the 9, 10, 13 and 15 groups, preferably a group of elementscomposed of iron (Fe), nickel (Ni), cobalt (Co), phosphorus (P), boron(B), platinum (Pt), palladium (Pd), rhodium (Rh) and ruthenium (Ru),more preferably a group of elements composed of cobalt (Co), nickel(Ni), phosphorus (P) and boron (B); these compounds may be used singlyor as a mixture of two kinds or more.

[0080] The aforementioned compounds to be used as a particle growthinhibiter yield ions in an aqueous solution, either anions or cations,and anions are present as oxyanions such as Mo₄ ²⁻, WO₄ ²⁻, PO₄ ³⁻ andBO₃ ³⁻ or as metal carbonyl anions while cations are present as metalcations such as Ni²⁺ and Co²⁺. When plural kinds of elements possessingcatalytic activity for hydrotreating such as mentioned above aresupported on a catalyst carrier, they may be supported on the carrier insuccession, one supported repeatedly plural times before another, orthey may be supported simultaneously as a mixture on the carrier.

[0081] The compounds yielding particularly suitable oxyanions includeammonium molybdates [(NH₄)₆Mo₇O₂₄.4H₂O (NH₄)₂MoO₄, (NH₄)MoO₇], sodiummolybdate (Na₂MoO₄.2H₂O), molybdic acid (H₂MoO₄, H₂MoO₃.H₂O), molybdenumpentachloride MoCl₅), silicomolybdic acid (H₄SiMo₁₂O₄₀.nH₂O), tungsticacid (H₂WO₄), ammonium tungstate [5(NH)₄O.12WO₃.H₂O,3(NH)₂O.12WO₃.nH₂O], sodium tungstate (Na₂WO₄.2H₂O), H₃PO₄, HPO₃,H₄P₂O₇, P₂O₅, NH₄H₂PO₄, (NH₄)₂HPO₄, (NH)₃PO₄.H₂O, H₃[PO₄W₁₂O₃₆].5H₂O andsalts of heteropolyacids containing Mo or W.

[0082] The metal salts suitable for yielding metal carbonyl anionsinclude (NEt₄)[Mo(CO)₅(OOCCH₃)], Mo(CO)₆—NEt₃-EtSH, Ru₃(CO)₁₂—NEt₃-EtSH,(η-C₆H₄Me)₂Mo₂Co₂S₃(CO)₄. W(CO)₆ and W(CO)₆—NEt₃-EtSH. The metal saltssuitable for yielding metal cations include nickel nitrate[Ni(NO₃)₂.6H₂O], nickel sulfate (NiSO₄.6H₂O), nickel chloride (NiCl₂),nickel acetate [Ni(CH₃CO₂)₂.4H₂O], cobalt acetate [Co(CH₃CO₂)₂.6H₂O],cobalt nitrate [Co(NO₃)₂.6H₂O], cobalt sulfate (CoSO₄.7H₂O) and cobaltchloride (CoCl₂.6H₂O).

[0083] As for the amount of the aforementioned compounds of elementspossessing catalytic activity for hydrotreating to be added as aparticle growth inhibiter in order to effect an ion exchange with thehydroxyl groups of hydrous titanium oxide, the amount of the principalcatalyt element molybdenum (Mo) and/or tungsten (W) to be supported on acatalyst carrier is controlled preferably at 15 wt % or more, morepreferably at 20-40 wt %, on the oxide basis and the amount of the totalcatalyst components to be supported on a catalyst carrier is controlledpreferably at 20 wt % or more, more preferably at 30-47 wt %, on theoxide basis in order to increase the selectivity of the denitrogenationreaction thereby improving performance of both desulfurization anddenitrogenation. When the amount of the principal catalyst elementsmolybdenum (Mo) and/or tungsten (W) supported on a catalyst carrier isless than 15 wt %, it is not possible to obtain the desiredhydrotreating activity against hydrocarbon oils.

[0084] Moreover, in order to obtain a hydrotreating catalyst forhydrocarbon oils which gives an excellent performance m desulfurizationand denitrogenation with minimal consumption of hydrogen, the amount ofion exchange is preferably controlled so that it is 0.06-0.46 atom per 1titanium atom for the principal catalyst element and 0.02-0.26 atom per1 titanium atom for the promoter element or 0.08-0.82 atom per 1titanium atom for the sum total of the principal and promoter elements.

[0085] Several useful methods such as the following are available forpreparing a catalyst supported on titanium oxide possessing theaforementioned catalytic activity for hydrotreating; hydrous titaniumoxide is brought into contact with the ions of the principal catalystelement and the ions of the promoter element, either together orseparately, to effect ion exchange, then the pH is finally adjusted to avalue in the range of 3-9 and the ion-exchanged product is molded, driedand calcined; hydrous titanium oxide is added to a impregnating solutioncontaining the ions of the principal catalyst element and those of thepromoter element, ion exchange is effected at pH 1-7 or pH 9-11, and theion-exchanged product is filtered, molded, dried and calcined; hydroustitanium oxide is brought into contact with the ions of principalcatalyst elements consisting of molybdenum (Mo) and/or tungsten (W) andthe ions of one kind or more of promoter elements selected from cobalt(Co), nickel (Ni), phosphorus (P) and boron (13) and the ion-exchangedproduct is filtered, molded, dried and calcined.

[0086] A hydrous 4 group metal oxide (hydrous titanium oxide) preparedin the aforementioned manner is then filtered, dehydrated, dried andcalcined to give a porous 4 group metal oxide (porous titanium oxide)and here the hydrous 4 group metal oxide is dried or dehydrated to thewater content of 200-900 wt %, preferably 250-600 wt %, on the solidbasis, molded into a specified configuration, dried at 40-350° C.,preferably at 80-200° C., for 0.5-24 hours, preferably 0.5-5 hours, andthen calcined at 350-1200° C., preferably at 400-700° C., for 0.5-24hours, preferably 0.5-10 hours.

[0087] The porous 4 group metal oxide of this invention obtained in thismanner normally has a pore sharpness degree of 50% or more. Poroustitanium oxide or a porous 4 group metal oxide in which the 4 groupmetal M is titanium (Ti) has a pore sharpness degree of 50% or more anda pore volume of 0.2 mug or more, occasionally 0.3 ml/g or more, evenwhen calcined at 500° C. for 3 hours.

[0088] Titanium oxide of this invention supporting an element havingcatalytic activity for hydrotreating is porous titanium oxide whichgives excellent performance in desulfurization and denitrogenation as ahydrotreating catalyst for hydrocarbon oils and is capable of removingboth sulfur and nitrogen components from hydrocarbon oils effectively inthe presence of hydrogen at a reaction temperature of 280-400° C., areaction pressure of 2-15 MPa, an LHSV of 0.3-10 hr⁻¹ and a hydrogen/oilratio of 50-500 Nl/l.

BRIEF DESCRIPTION OF THE DRAWINGS

[0089]FIG. 1 is a graph illustrating the relationship between the heattreatment temperature and the specific surface area of the titaniahydrosol which was obtained m Example 19 and heat-treated before theaddition of a particle growth inhibiter.

[0090]FIG. 2 is a graphic model illustrating the method for obtainingthe pore asymmetric coefficient N.

[0091]FIG. 3 is a graph investigating the effect of adding a particlegrowth inhibiter to hydrous titanium oxide by the use of porous titaniumoxide of Examples 1 and 9 and Comparative Examples 2 through 4.

[0092]FIG. 4 is a graph illustrating the relationship between the sulfurremoval and the nitrogen removal in hydroprocessing by the use of thetitania catalyst of Examples 27 through 30 and 32, the Co/Mo-aluminacatalyst of Comparative Example 11 and the Ni/Mo-alumina of ComparativeExample 12.

[0093]FIG. 5 is a graph showing the results of electron probemicroanalysis (EPMA) of the hydrotreating catalyst obtained in Example38.

[0094]FIG. 6 is a graph showing the X-ray diffraction pattern of thehydrotreating catalyst obtained in Example 38.

[0095]FIG. 7 is a graph showing the X-ray diffraction pattern ofmolybdenum oxide (MoO₃).

[0096]FIG. 8 is a graph illustrating the relationship between thenitrogen removal and the hydrogen consumption obtained in the testsconducted on the titania catalyst of Examples 33 and 34 and the aluminacatalyst of Comparative Examples 11 and 12 by varying the liquid hourlyspace velocity in the range of 1-3.0 hr⁻¹.

PREFERRED EMBODIMENTS OF THE INVENTION

[0097] Suitable modes of practice of this invention will be describedconcretely below with reference to the accompanying examples andcomparative examples.

[0098] In this invention, a variety of physical properties of poroustitanium oxide and hydrous titanium oxide were determined by thefollowing methods.

[0099] [Pore Volume (TPV) and Pore Size Distribution]

[0100] The pore volume and pore size distribution of porous titaniumoxide were determined by the method based on mercury penetration underpressure with the aid of an instrument, Autopore 9200 available fromShimadzu Corporation. The method is described in detail in E. W.Washburn, Proc. Natl. Acad. Sci., 7, 115 (1921), H. L. Ritter and L. E.Drake, Ind. Eng. Chem. Anal., 17, 782, 787 (1945), L. C. Drake, Ind.Eng. Chem., 41, 780 (1949) and H. P Grace, J. Amer. Inst. Chem. Emgrs.,2, 307 (1965). The measurements were made at a surface tension ofmercury of 0.48 N/m and a contact angle of 140° while varying theabsolute mercury pressure from 0.08 to 414 MPa.

[0101] [Pore Sharpness Degree]

[0102] A cumulative pore distribution curve is measured by a mercuryporosimeter and the pore diameter at ½ PV of the total pore volume (TPV)or the median diameter is obtained from the ordinate denoting thecumulative pore volume and the abscissa denoting the pore diameter (Å).Following this, the pore volume (PVM) contained in the range of the porediameter within ±5% of the logarithnic value of the median diameter isobtained and the pore sharpness degree which shows sharpness of poredistribution is obtained from the pore volume (PVM) and the total porevolume (PVT) as follows;

Pore sharpness degree=[pore volume (PVT/total pore volume (PVT)]×100.

[0103] The pore sharpness degree defined here serves as a factor forevaluating the degree of pores optimal for the reaction relative to thetotal pore volume and the greater the pore sharpness degree, the sharperthe pore distribution becomes or the more favorable the situationbecomes.

[0104] [Crystal Structure]

[0105] The crystal structures of the catalyst and the catalyst carrierwere determined by X-ray diffractometry with the aid of an instrument,PW3710 available from Phillips.

[0106] [Specific Surface Area]

[0107] The three-point BET specific surface area of porous titaniumoxide was determined with the aid of an instrument, Macsorb Model 1201available from Mountec. The method is described in detail in an articleby S. Brunauer, P. H. Emmet, and E. Teller, J. Am. Chem. Soc., 60, 309(1938).

[0108] [Pore Volume (TMV)]

[0109] The pore volume of porous titanium oxide was determined with theaid of a mercury porosimeter, Autopore 9200 available from ShimadzuCorporation in accordance with the method based on mercury penetrationunder pressure. The method is described in detail in E. W. Washburn,Proc. Natl. Acad. Sci., 7, 115 (1921), H. L. Ritter and L. E. Drake,Ind. Eng. Chem. Anal., 17, 782, 787 (1945), L. C. Drake, Ind. Eng.Chem., 41, 780 (1949) and H. P. Grace, J. Amer. Inst. Chem. Engrs., 2,307 (1965). The measurements were made at a surface tension of mercuryof 0.48 N/m and a contact angle of 140° while varying the absolutemercury pressure from 0.08 to 414 MPa.

[0110] [Pore Asymmetric Coefficient N]

[0111] The pore asymmetric coefficient N defined by N=(A−C)/(B−A) wasobtained from FIG. 2 showing the relationship between the cumulativepore volume (ordinate) determined by a mercury porosimeter and the porediameter (abscissa: expressed in logarithm). That is, the logarithmicvalues of the pore diameter corresponding to the 50% pore volume, 2%pore volume and 98% pore volume were respectively taken as A, B and Cand the pore asymmetric coefficient N was expressed as the ratio of thedistance between C and A to that between B and A.

[0112] [Mechanical Strength (Side Crushing Strength:SCS)]

[0113] The mechanical strength (Side Crushing Strength:SCS) wasdetermined with the aid of a Kiya strength tester. A cylindricalextruded form with a length of 6 mm or less was compressed by a diskwith a diameter of 10 mm and the mechanical strength was obtained bydividing the load applied at the time of breakage by the length of thecylindrical extruded form as follows;

SCS=W/L

[0114] wherein W (kg) is the load applied at the time of breakage and L(mm) is the length of the cylindrical extruded form.

EXAMPLE 1

[0115] (Step for Synthesis of Hydrous Titanium Oxide Particles)

[0116] Silicon tetrachloride (SiCl₄) was used as a particle growthinhibiter of hydrous titanium oxide. To a vessel containing 5500 g of anaqueous solution of silicon tetrachloride (concentration of silicon,0.29 g/l computed as SiO₂) were added 165 g of an aqueous solution oftitanium tetrachloride with a concentration of 500 g/l and 166 g of 14wt % ammonia water to synthesize a hydrosol slurry of hydrous titaniumoxide. The temperature for this synthesis was 60° C.

[0117] A pH swing operation was performed on the hydrosol slurry ofhydrous titanium oxide thus obtained by adding 165 g of an aqueoussolution of titanium tetrachoride with a concentration of 500 g/l,returning the pH to the dissolving range of hydrous titanium oxide onthe acidic side, and then adding 166 g of 14 wt % ammonia water to shiftthe pH of the slurry to the precipitating range of hydrous titaniumoxide on the alkaline side, and another pH swing operation was performedto give hydrous titanium oxide particles. The pH of the final hydrosolslurry of hydrous titanium oxide was adjusted to 5.

[0118] (Steps for Filtration and Washing)

[0119] The synthesized hydrosol slurry of hydrous titanium oxide isfiltered, washed with 7.5 1 of water to remove chlorine and ammoniumions and the procedure of filtration and washing was repeated twice.Finally, filtration by suction gave a gel of hydrous titanium oxidewhich had a water content (structural water+free water) of 300 wt % onthe solid basis.

[0120] (Step for Extrusion Molding)

[0121] The gel of hydrous titanium oxide synthesized by application ofthe pH swing operation was molded into a cylindrical form by the use ofa piston type gel extrusion molder equipped with a 1.8 mm-diameter die.

[0122] (Steps for Drying and Calcining)

[0123] The cylindrical molded form of the hydrogel of hydrous titaniumoxide obtained in the extrusion molding step was dried in a dryer at120° C. for 3 hours and the dried form was calcined in an electric ovenat 500° C. for 3 hours to give porous titanium oxide. The calcined formwas allowed to cool in a desiccator.

[0124] The properties of the porous titanium oxide thus obtained areshown in Table 1. TABLE 1 Example 1 Raw material species TiCl₄ x incomposition formula 0.78 y in composition formula 12.5 PropertiesTitanium oxide content (wt %) 97.3 Specific surface area (m²/g) 187 Porevolume (TPV) (ml/g) 0.36 Pore sharpness degree (%) 78

EXAMPLE 2

[0125] Porous titanium oxide was obtained as in Example 1 with theexception of using an aqueous solution of phosphoric acid (concentrationof phosphorus, 0.25 g/l computed as P₂O₅) as a particle growth inhibiterof hydrous titanium oxide and setting the synthesis temperature at 80°C.

[0126] The properties of the porous titanium oxide thus obtained areshown in Table 2.

EXAMPLE 3

[0127] Porous titanium oxide was obtained as in Example 1 with theexception of using an aqueous solution of magnesium chloride hexahydrate(concentration of magnesium, 0.08 g/l computed as MgO) as a particlegrowth inhibiter of hydrous titanium oxide, setting the synthesistemperature at 100° C., performing the pH swing operation twice undersuch conditions as to produce the same amount of hydrous titanium oxideas in Example 1 and adjusting the pH of the final hydrosol slurry ofhydrous titanium oxide to 8.

[0128] The properties of the porous titanium oxide thus obtained areshown in Table 2.

EXAMPLE 4

[0129] Porous titanium oxide was obtained as in Example 1 with theexception of using an aqueous solution of calcium chloride dihydrate(concentration of calcium, 0.17 g/l computed as CaO) as a particlegrowth inhibiter of hydrous titanium oxide, setting the synthesistemperature at 120° C., performing the pH swing operation six timesunder such conditions as to produce the same amount of hydrous titaniumoxide as in Example 1 and adjusting the pH of the final hydrosol slurryof hydrous titanium oxide to 8.

[0130] The properties of the porous titanium oxide thus obtained areshown in Table 2.

EXAMPLE 5

[0131] Porous titanium oxide was obtained as in Example 1 with theexception of using an aqueous solution of barium chloride dihydrate(concentration of barium, 0.24 g/l computed as BaO) as a particle growthinhibiter of hydrous titanium oxide, setting the synthesis temperatureat 140° C. and adjusting the pH of the final hydrosol slurry of hydroustitanium oxide to 8.

[0132] The properties of the porous titanium oxide thus obtained areshown in Table 2.

EXAMPLE 6

[0133] Porous titanium oxide was obtained as in Example 5 with theexception of using an aqueous solution of zirconium oxychlorideoctahydrate (concentration of zirconium, 0.33 g/l computed as ZrO₂) as aparticle growth inhibiter of hydrous titanium oxide and setting thesynthesis temperature at 140° C.

[0134] The properties of the porous titanium oxide thus obtained areshown in Table 2.

EXAMPLE 7

[0135] Porous titanium oxide was obtained as in Example 1 with theexception of using an aqueous solution of manganese chloridetetrahydrate (concentration of manganese, 0.22 g/l computed as MnO) as aparticle growth inhibiter of hydrous titanium oxide, setting thesynthesis temperature at 180° C., performing the pH swing operationtwice under such conditions as to produce the same amount of hydroustitanium oxide as in Example 1 and adjusting the pH of the finalhydrosol slurry of hydrous titanium oxide to 8.

[0136] The properties of the porous titanium oxide thus obtained areshown in Table 2.

EXAMPLE 8

[0137] Porous titanium oxide was obtained as in Example 1 with theexception of using an aqueous solution of aluminum chloride(concentration of aluminum, 0.30 g/l computed as Al₂O₃) as a particlegrowth inhibiter of hydrous titanium oxide, setting the synthesistemperature at 40° C. and adjusting the pH of the final hydrosol slurryof hydrous titanium oxide to 7.

[0138] The properties of the porous titanium oxide thus obtained areshown in Table 2. TABLE 2 Ex- Ex- ample 2 ample 3 Example 4 Example 5Example 6 Example 7 Example 8 Raw material species TiCl₄ TiCl₄ TiCl₄TiCl₄ TiCl₄ TiCl₄ TiCl₄ x in composition formula 0.75 0.80 0.30 0.550.50 0.65 1.0 y in composition formula 12.5 12.5 13.0 12.7 12.8 12.612.3 Properties Titanium oxide content (wt %) 97.5 98.8 97.1 97.7 97.197.6 97.3 Specific surface area (m²/g) 158 93 97 134 125 100 114 Porevolume (TPV) (ml/g) 0.33 0.33 0.80 0.34 0.33 0.42 0.37 Pore sharpnessdegree (%) 61 70 55 79 76 60 78

[0139] In each of the examples in Tables 1 and 2, titanium oxide whosepreparation is the target of this invention has a purity of 97 wt % ormore, a specific surface area of 80 m²/g or more, a pore volume (PVT) of0.3 ml/g or more and a pore sharpness degree of 50% or more.

EXAMPLE 9

[0140] Porous titanium oxide was obtained as in Example 1 with theexception of using an aqueous solution of silicon tetrachloride(concentration of silicon, 0.05 g/l computed as SiO₂) as a particlegrowth inhibiter of hydrous titanium oxide.

[0141] The properties of the porous titanium oxide thus obtained areshown in Table 3.

EXAMPLE 10

[0142] Porous titanium oxide was obtained as in Example 1 with theexception of using an aqueous solution of silicon tetrachloride(concentration of silicon, 0.02 g/l computed as SiO₂) and phosphoricacid (concentration of phosphorus, 0.09 g/l computed as P₂O₅) asparticle growth inhibiters of hydrous titanium oxide, setting thesynthesis temperature at 80° C. and performing the pH swing operationsix times under such conditions as to produce the same amount of hydroustitanium oxide as in Example 1.

[0143] The properties of the porous titanium oxide thus obtained areshown in Table 3.

EXAMPLE 11

[0144] Porous titanium oxide was obtained as in Example 1 with theexception of using an aqueous solution of silicon tetrachloride(concentration of silicon, 0.15 g/l computed as SiO₂), calcium chloridedihydrate (concentration of calcium, 0.15 g/l computed as CaO) andmagnesium chloride hexahydrate (concentration of magnesium, 0.04 g/lcomputed as MgO) as a particle growth inhibiter while using the aqueoussolution as an aqueous solvent in the step for synthesis, setting thesynthesis temperature at 100° C., performing the pH swing operation ninetimes under such conditions as to produce the same amount of hydroustitanium oxide as in Example 1 and adjusting the pH of the finalhydrosol slurry of hydrous titanium oxide to 7.

[0145] The properties of the porous titanium oxide thus obtained areshown in Table 3.

EXAMPLE 12

[0146] Porous titanium oxide was obtained as in Example 1 with theexception of preparing the hydrosol slurry of hydrous titanium oxidewithout using a particle growth inhibiter of hydrous titanium oxide andusing an aqueous solution of silicon tetrachloride (concentration ofsilicon, 0.03 g/l computed as SiO₂), calcium chloride (concentration ofcalcium, 0.03 g/l computed as CaO) and magnesium chloride (concentrationof magnesium, 0.01 g/l computed as MgO) as washing water in the step forwashing the titania hydrogel slurry.

[0147] The properties of the porous titanium oxide thus obtained areshown in Table 3.

EXAMPLE 13

[0148] The washed hydrogel of hydrous titanium oxide was obtained as inExample 1 with the exception of not using a particle growth inhibiter ofhydrous titanium oxide.

[0149] To 50 g as TiO₂ of the hydrogel of hydrous titanium oxide [watercontent (structural water+free water), 300 wt % on the solid basis] wasadded 0.92 g computed as P₂O₅ of ammonium dihydrogen phosphate powdersas a particle growth inhibiter and the two were kneaded to give ahomogeneous mixture. Thereafter, the same procedure as in Example 1 wasfollowed to give porous titanium oxide.

EXAMPLE 14

[0150] A dried molded form of hydrous titanium oxide corresponding to 50g as TiO₂ was immersed in 200 ml of a solution of phosphoric acid(concentration of phosphorus, 4.8 g/l computed as P₂O₅) and thereafterthe procedure of Example 1 was followed to give porous titanium oxide.

[0151] The properties of the porous titanium oxide thus obtained areshown in Table 3. TABLE 3 Exam- Exam- Example 9 Example 10 Example 11Example 12 ple 13 ple 14 Raw material species TiCl₄ TiCl₄ TiCl₄ TiCl₄TiCl₄ TiCl₄ x in composition formula 0.78 0.35 0.13 0.78 0.78 0.78 y incomposition formula 12.5 12.9 13.2 12.5 12.5 — Properties Titanium oxidecontent (wt %) 98.4 97.4 97.1 97.6 97.4 97.4 Specific surface area(m²/g) 109 82 97 146 162 167 Pore volume (TPV) (ml/g) 0.33 0.81 0.880.32 0.34 0.36 Pore sharpness degree (%) 73 63 52 82 60 56

[0152] Examples 10 and 11 relate to the cases where a plurality ofparticle growth inhibiters of hydrous titanium oxide are added to thesynthesis solvent, Example 12 to the case where a particle growthinhibiter of hydrous titanium oxide is added during washing of the geland Examples 13 and 14 to the cases where a particle growth inhibiter isadded to porous titanium oxide by kneading with the hydrous titaniumoxide gel or impregnating the dried material. In each case, titaniumoxide whose preparation is the target of this invention has a purity of97 wt % or more, a specific surface area of 80 m²/g or more, a porevolume (PVT) of 0.3 ml/g or more and a pore sharpness degree of 50% ormore.

COMPARATIVE EXAMPLE 1

[0153] To a vessel containing 2 l of boiled water was added 0.3 l of anaqueous solution of titanium tetrachloride with a concentration of 500g/l and then 0.4 l of 14 wt % ammonia water was added while keeping thetemperature of the liquid at 95° C. to give a hydrosol slurry of hydroustitanium oxide. Thereafter, addition of the aqueous solution of titaniumtetrachloride and the ammonia water was repeated twice under the boilingcondition to give hydrous titanium oxide particles. The pH of the finalhydrosol slurry of hydrous titanium oxide was adjusted to 7. Thereafter,the same procedure as in Example 1 was followed to give porous titaniumoxide.

[0154] The properties of the porous titanium oxide thus obtained areshown in Table 4.

COMPARATIVE EXAMPLE 1

[0155] Porous titanium oxide was obtained as in Example 1 with theexception of synthesizing hydrous titanium oxide only in one reaction inan amount corresponding to that obtained after three pH swing operationsin Example 1 without using a particle growth inhibiter of hydroustitanium oxide and without performing a pH swing operation and adjustingthe pH of the hydrosol slurry of hydrous titanium oxide to 7.

[0156] The properties of the porous titanium oxide thus obtained areshown in Table 4.

COMPARATIVE EXAMPLE 2

[0157] Porous titanium oxide was obtained as in Example 1 with theexception of using an aqueous solution of silicon tetrachloride with aconcentration of 0.009 g/l computed as SiO₂ in the step for thesynthesis of hydrous titanium oxide.

[0158] The properties of the porous titanium oxide thus obtained areshown in Table 4.

COMPARATIVE EXAMPLE 3

[0159] Porous titanium oxide was obtained as in Example 1 with theexception of using an aqueous solution of silicon tetrachloride with aconcentration of 0.60 g/l computed as SiO₂ in the step for the synthesisof hydrous titanium oxide.

[0160] The properties of the porous titanium oxide thus obtained areshown in Table 4.

COMPARATIVE EXAMPLE 4

[0161] Porous titanium oxide was obtained as in Example 1 with theexception of adjusting the pH of the final hydrosol slurry of hydroustitanium oxide to 8 in the step for the synthesis of hydrous titaniumoxide.

[0162] The properties of the porous titanium oxide thus obtained areshown in Table 4.

COMPARATIVE EXAMPLE 5

[0163] Porous titanium oxide was obtained as in Example 1 with theexception of using an aqueous solution of magnesium chloride with aconcentration of 0.08 g/l computed as MgO in the step for the synthesisof hydrous titanium oxide and adjusting the pH of the final hydrosolslurry of hydrous titanium oxide to 4.

[0164] The properties of the porous titanium oxide thus obtained areshown in Table 4. TABLE 4 Comparative Comparative ComparativeComparative Comparative Example 1 Example 2 Example 3 Example 4 Example5 Raw material species TiCl₄ TiCl₄ TiCl₄ TiCl₄ TiCl₄ x in compositionformula 1.30 0.75 0.75 0.75 0.75 y in composition formula 12.0 12.5 12.512.5 12.5 Properties Titanium oxide content (wt %) 99.2 99.2 95.4 88.999.2 Specific surface area (m²/g) 60 67 199 224 78 Pore volume (TPV)(ml/g) 0.16 0.15 0.28 0.36 0.17 Pore sharpness degree (%) 71 75 48 45 74

[0165] Comparative Example 1 in Table 4 relates to porous titanium oxideprepared in accordance with Example 32 described in the specification ofJP 56-120,508 A on a ⅕ scale while performing the pH swing operationthree times and porous titanium oxide in Comparative Example 1 wasprepared without addition of a particle growth inhibiter of hydroustitanium oxide. The specific surface area in both Comparative Example 1and Comparative Example 1 is less than 80 m²/g. Comparative Example 2relates to the case where the addition of a particle growth inhibiter isless than 0.1 wt % and the specific surface area is less than 80 m²/gwhile Comparative Examples 3 and 4 relate to the case where the additionof a particle growth inhibiter is more than 3 wt % and the purity oftitanium oxide is less than 97 wt %. Comparative Example 5 relates tothe case where a particle growth inhibiter of hydrous titanium oxidewhich is presumably present as polyvalent cations in the synthesissolvent or magnesium chloride hexahydrate was added and the pH of thefinal hydrosol slurry of hydrous titanium oxide was adjusted to 4 whichis lower than the isoelectric point of anatase crystals and it is seenthat very little magnesium was taken into titanium oxide under thiscondition.

[0166] The effect of adding a particle growth inhibiter of hydroustitanium oxide will be explained on the basis of the results obtained inExamples 1 and 9 and Comparative Examples 2 through 4.

[0167] To a vessel containing 5500 g of water was added 150 g of anaqueous solution of sodium silicate with a concentration of 100 g/l,then the pH was adjusted to 4 by adding a 20 wt % aqueous solution ofsulfuric add to give a hydrosol slurry of hydrous silicon oxide.Thereafter, the same adding procedure as the foregoing was repeatedtwice or the pH swing operation was repeated three times to give ahydrosol slurry of hydrous silicon oxide. After this, the procedure ofExample 31 was followed to give porous silicon oxide. The porous siliconoxide with a purity of 99.4 wt % thus obtained had a specific surfacearea of 650 m²/g. The specific surface area of a mixture of thishigh-purity porous silicon oxide and the porous titanium oxide with apurity of 99.2 wt % prepared in Comparative Example 2 can be expressedby the mix ratio of silicon oxide and titanium oxide.

[0168] Porous titanium oxide of Examples 1 and 9 and ComparativeExamples 2 through 4 contains porous silicon oxide originating insilicon tetrachloride added as a particle growth inhibiter of hydroustitanium oxide during the synthesis. Therefore, the effect of increasingthe specific surface area produced by a particle growth inhibiter ofhydrous titanium oxide alone exclusive of the same effect produced bythe added silicon tetrachloride can be expressed by the difference inspecific surface area (an increment of specific surface area) betweenmixtures of high-purity titanium oxide and high-purity silicon oxideprepared in the same ratio as in Examples 1 and 9 and ComparativeExamples 2 through 4.

[0169] In order to confirm the effect of adding a particle growthinhibiter of hydrous titanium oxide alone in Examples 1 and 9 andComparative Examples 2 through 4, an increment of specific surface areawas obtained by subtracting the specific surface area originating insilicon oxide and corresponding to the content of silicon oxide inporous titanium oxide in Examples 1 and 9 and Comparative Examples 2through 4.

[0170] The results are shown in FIG. 3 in which the content of siliconoxide in porous titanium oxide is plotted on the x axis and theincrement of specific surface area on the y axis.

[0171] As is apparent from FIG. 3, the increment of specific surfacearea is large until the content of silicon oxide reaches 3 wt % and theincremet is particularly pronounced up to 2 wt %; thus it is seen that aparticle growth inhibiter of hydrous titanium oxide manifests aconsiderable effect for increasing the specific surface area. However,where the content of silicon oxide is less than 0.1 wt % as in the caseof Comparative Example 2, a specific surface area of 80 m²/g or morewhich is the target of this invention is not attained. The effect forincreasing the specific surface area gradually decreases as the contentof silicon oxide exceeds 3 wt % and addition of a particle growthinhibiter of hydrous titanium oxide in excess of this value produces asmaller effect.

EXAMPLE 15

[0172] (Step for Synthesis of Hydrous Titanium Oxide Particles)

[0173] To 11 kg of water was added 330 g of an aqueous solution oftitanium tetrachloride with a concentration of 500 g/l to adjust the pHof the synthesis solution to 1.5, and 340 ml of 14 wt % ammonia waterwas added to shift the pH to 6.5 and give a hydrosol slurry of hydroustitanium oxide. The temperature during this synthesis was 60° C.

[0174] To the hydrosol slurry of hydrous titanium oxide was added 300 gof an aqueous solution of titanium tetrachloride with a concentration of500 g/l to return the pH of the slurry to 1.5 or to the acidic side ofhydrous titanium oxide, then 355 ml of 14 wt % ammonia water was addedto shift the pH of the slurry to 6.3 near the isoelectric point ofhydrous titanium oxide, and this pH swing operation was repeated twiceor four times to give hydrous titanium oxide particles.

[0175] The hydrous titanium oxide thus synthesized was subjected to thesteps for filtration and washing, the step for extrusion molding and thesteps for drying and calcining described in the aforementioned Example 1to give porous titanium oxide.

[0176] The properties of the porous titanium oxide prepared from thehydrous titanium oxide are shown in Table 5. TABLE 5 Example 15 Rawmaterial TiCl₄ TiCl₄ species Number of pH swing 2 4 operations x incomposition — — formula y in composition — — formula Properties Specificsurface area (m²/g) 183 168 Pore volume (TPV) (ml/g) 0.25 0.43 Poresharpness degree (%) 78 63 Pore asymmetric (—) 1.71 1.92 coefficient (N)Mechanical strength (kg/mm) 1.0 0.6 (SCS) Median diameter (nm) 6.4 9.9

EXAMPLE 16

[0177] To 11 kg of water was added 330 g of an aqueous solution oftitanium tetrachoride with a concentration of 500 g/l to adjust the pHof the synthesis solution to 1.5, and 355 ml of 14 wt % ammonia waterwas added to shift the pH to 7.5 and give a hydrosol slurry of hydroustitanium oxide. The temperature during this synthesis was 75° C.

[0178] To the hydrosol slurry of hydrous titanium oxide was added 330 gof an aqueous solution of titanium tetrachloride with a concentration of500 g/l to return the pH of the slurry to 1.5 or to the acidic side ofhydrous titanium oxide, then 355 ml of 14 wt % ammonia water was addedto shift the pH of the slurry over the isoelectric point of hydroustitanium oxide to 7.5, and this pH swing operation was repeated fourtimes to give hydrous titanium oxide particles.

[0179] Porous titanium oxide was prepared from the hydrous titaniumoxide as in the aforementioned Example 15. The properties of the poroustitanium oxide thus obtained are shown in Table 5.

EXAMPLE 17

[0180] To 11 kg of water was added 300 ml of 14 wt % ammonia water toadjust the pH to 9, and the pH swing operation was performed five timesin total between pH 3.8 on the acidic side and pH 7.5 over theisoelectric point of hydrous titanium oxide by the use of 330 g of anaqueous solution of titanium tetrachloride with a concentration of 500g/l and 355 ml of 14 wt % ammonia water to give porous titanium oxide asin Example 15 with the exception of spending approximately 2 minutes atpH 6 during the pH swing operation. The properties of the poroustitanium oxide thus obtained are shown in Table 6.

EXAMPLE 18

[0181] To 11 kg of water was added NaOH to adjust the pH to 11.5, thenan aqueous solution of titanium tetrachloride with a concentration of500 g/l was added to shift the pH to 5.8 and this pH swing operation wasrepeated three times in total while following the rest of the procedurein Example 15 to give porous titanium oxide. The properties of theporous titanium oxide thus obtained are shown in Table 6. TABLE 6Example Example Example 16 17 18 Raw material species TiCl₄ TiCl₄ TiCl₄x in composition formula — — — y in composition formula — — — PropertiesSpecific surface area (m²/g) 176 125 169 Pore volume (TPV) (ml/g) 0.290.23 0.30 Pore sharpness degree (%) 65 61 62 Pore asymmetric coefficient(N) (—) 3.46 3 3.3 Mechanical strength (SCS) (kg/mm) 0.9 1.1 0.8 Mediandiameter (nm) 7.2 9.0 7.1

COMPARATIVE EXAMPLE 6

[0182] Porous titanium oxide was prepared as in Example 15 with theexception of performing the pH swing operation between pH 2.0 in the lowpH range and pH 4.5 in the high pH range four times in total by the useof 330 g of an aqueous solution of titanium tetrachloride with aconcentration of 500 g/l and 355 ml of 14 wt % ammonia water. Theproperties of the porous titanium oxide thus obtained are shown in Table7.

COMPARATIVE EXAMPLE 7

[0183] Porous titanium oxide was prepared as in Example 15 with theexception of performing the pH swing operation between pH 4.5 in the lowpH range and pH 6.5 in the high pH range four times in total by the useof 330 g of an aqueous solution of titanium tetrachloride with aconcentration of 500 g/l and 355 ml of 14 wt % ammonia water. Theproperties of the porous titanium oxide thus obtained are shown in Table7.

COMPARATIVE EXAMPLE 8

[0184] Porous titanium oxide was prepared as in Example 15 with theexception of preparing a hydrosol slurry of hydrous titanium oxide byadding 355 ml of 14 wt % ammonia water and then adding 330 g of anaqueous solution of titanium tetrachloride with a concentration of 500g/l and performing the pH swing operation between pH 9.5 in the alkalirange and pH 7.5 in the low pH range four times in total by the use of355 ml of 14 wt % ammonia water and 330 g of an aqueous solution oftitanium tetrachloride with a concentration of 500 g/l. The propertiesof the porous titanium oxide thus obtained are shown in Table 7. TABLE 7Comparative Comparative Comparative Example 6 Example 7 Example 8 Rawmaterial species TiCl₄ TiCl₄ TiCl₄ x in composition formula — — — y incomposition formula — — — Properties Specific surface area (m²/g) 105146 115 Pore volume (TPV) (ml/g) 0.15 0.32 0.15 Pore sharpness degree(%) 43 40 48 Pore asymmetric coefficient (N) (—) 5 6 5.2 Mechanicalstrength (SCS) (kg/mm) 0.8 0.4 0.9 Median diameter (nm) 6.7 13.0 6.3

[0185] (Step for Synthesis of Hydrous Titanium Oxide Particles)

[0186] To 10 kg of pure water was added 1500 g of an aqueous solution oftitanium tetrachloride with a concentration of 210 g/l to adjust the pHof the synthesis solution to 0.5, and then 2300 g of 14 wt % ammoniawater was added to shift the pH to 7.0 and give a hydrosol slurry ofhydrous titanium oxide. The temperature during this synthesis was 60° C.

[0187] To the hydrosol slurry of hydrous titanium oxide thus obtainedwas added 1500 g of an aqueous solution of titanium tetrachloride with aconcentration of 500 g/l to return the pH to 0.5 in the acid range ofhydrous titanium oxide (hydrosol dissolving pH range), 2800 ml of 14 wt% ammonia water was added to shift the pH to 7.0 (hydrosol precipitatingpH range), and this pH swing operation was repeated five times in totalto give hydrous titanium oxide particles.

[0188] (Steps for Filtration and Washing)

[0189] Following the completion of the aforementioned step for synthesisof hydrosol the hydrosol was filtered, the resulting cake was washedwith pure water repeatedly until the absence of chlorine (Cl⁻) in thefiltrate was confirmed by titration with silver nitrate to give titaniahydrosol.

[0190] (Step for Preparation of Dried Form)

[0191] The titania hydrosol obtained in the aforementioned manner wasfiltered by suction, dehydrated until the water content (structuralwater+free water) becomes approximately 50 wt %, molded by the use of a1.8 mm-diameter die, and dried at 120° C. for 3 hours to give a driedmolded form of titania.

[0192] (Step for Adding a Particle Growth Inhibiter)

[0193] The dried molded form of titania obtained above was immersed inan aqueous solution of ammonium paramolybdate with a concentrationcorresponding to 16.3 wt % of titanium oxide on the oxide basis, leftstanding at room temperature for 2 hours and filtered through a filterpaper 5 C to give molybdenum supported on titania.

[0194] (Steps for Drying and Calcining)

[0195] The molybdenum supported on titania was dried at 120° C. for 3hours and then calcined at 500° C. for 3 hours to give a molybdenumcatalyst supported on titania.

[0196] The properties of the molybdenum catalyst supported on titaniaare shown in Table 8.

EXAMPLE 20

[0197] The hydrosol after washing in Example 19 was immersed in anaqueous solution of ammonium paramolybdate with a concentrationcorresponding to 16.3 wt % of titanium oxide on the oxide basis, leftstanding at room temperature for 2 hours, filtered by suction, anddehydrated until the water content (structural water+free water) reached400 wt %. Molding by the use of a 1.5 mm-diameter die followed and themolded form was dried at 120° C. for 3 hours and then calcined at 500°C. for 3 hours to give a molybdenum catalyst supported on titania.

[0198] The properties of the catalyst thus obtained are shown in Table8.

EXAMPLE 21

[0199] A cobalt-molybdenum catalyst supported on titania was prepared asin Example 20 with the exception of using simultaneously cobalt nitrateand ammonium paramolybdate as particle growth inhibiters, respectivelyin an amount corresponding to 3.0 wt % and 10.0 wt % of titanium oxideon the oxide basis.

[0200] The properties of the catalyst thus obtained are shown in Table8.

EXAMPLE 22

[0201] The hydrosol after filtration in Example 19 was immersed in anaqueous solution of phosphoric add, ammonium paramolybdate and cobaltnitrate as particle growth inhibiters, respectively in an amountcorresponding to 2.0 wt %, 8.0 wt % and 2.9 wt % of titanium oxide onthe oxide basis, left standing at room temperature for 2 hours, filteredby suction, and dehydrated until the water content (structuralwater+free water) reached 400 wt % on the solid basis. Molding by theuse of a 1.8 mm-diameter die followed and the molded form was dried at120° C. for 3 hours and then calcined at 500° C. for 3 hours to give aphosphorus-molybdenum-cobalt catalyst supported on titania.

[0202] The properties of the catalyst thus obtained are shown in Table8. TABLE 8 Example 19 Example 20 Example 21 Example 22 Raw materialspecies TiCl₄ TiCl₄ TiCl₄ TiCl₄ x in composition formula 0.21 0.53 0.530.53 y in composition formula 0.3 17.2 17.2 17.2 Properties Specificsurface area (m²/g) 129 142 115 149 Pore volume (TPV) (ml/g) 0.42 0.350.33 0.41 Pore sharpness degree (%) 54 65 — —

EXAMPLE 23

[0203] A phosphorus-molybdenum-nickel catalyst supported on titania wasprepared as in Example 22 with the exception of using simultaneouslyphosphoric acid, ammonium paramolybdate and nickel nitrate as particlegrowth inhibiters, respectively in an amount corresponding to 2.0 wt %,8.0 wt % and 2.0 wt % of titanium oxide on the oxide basis.

[0204] The properties of the catalyst thus obtained are shown in Table9.

EXAMPLE 24

[0205] A nickel-molybdenum-cobalt catalyst supported on titania wasprepared as in Example 22 with the exception of using simultaneouslynickel nitrate, ammonium paramolybdate and cobalt nitrate as particlegrowth inhibiters, respectively in an amount corresponding to 2.0 wt %,8.0 wt % and 2.0 wt % of titanium oxide on the oxide basis.

[0206] The properties of the catalyst thus obtained are shown in Table9.

EXAMPLE 25

[0207] A phosphorus-tungsten-nickel catalyst supported on titania wasprepared as in Example 20 with the exception of using simultaneouslyphosphorus, ammonium metatungstate and nickel nitrate as particle growthinhibiters, respectively in an amount corresponding to 2.0 wt %, 8.0 wt% and 2.0 wt % of titanium oxide on the oxide basis.

[0208] The properties of the catalyst thus obtained are shown in Table9.

EXAMPLE 26

[0209] Following the procedure of Example 19, zirconium oxychloride wasused as a raw material and a hydrogel of zirconia after filtration wasimmersed in an aqueous solution containing ammonium paramolybdate in anamount corresponding to 16.3 wt % of zirconium oxide on the oxide basis,left standing at room temperature for 2 hours, filtered by suction anddehydrated until the water content (structural water+free water) became400 wt % on the solid basis. Molding by the use of a 1.5 mm-diameter diefollowed and the resulting molded form was dried at 120° C. for 3 hoursand then calcined at 500° C. for 3 hours to give a molybdenum catalystsupported on zirconia.

[0210] The properties of the catalyst thus obtained are shown in Table9. TABLE 9 Example 23 Example 24 Example 25 Example 26 Raw materialspecies TiCl₄ TiCl₄ TiCl₄ Zirconium oxychloride x in composition formula0.53 0.53 0.53 0.30 y in composition formula 17.2 17.2 17.2 17.4Properties Specific surface area (m²/g) 167 105 133 103 Pore volume(TPV) (ml/g) 0.31 0.46 0.38 0.43 Pore sharpness degree (%) — — — —

COMPARATIVE EXAMPLE 9

[0211] The dried molded form of titania obtained in Example 19 beforeaddition of a particle growth inhibiter was calcined at 500° C. to givea titania carrier.

[0212] The properties of the titania carrier thus obtained are shown inTable 10.

COMPARATIVE EXAMPLE 10

[0213] A molybdenum catalyst supported on titania was prepared as inExample 19 with the exception of drying the molded form of titaniaobtained in Example 2 before addition of a particle growth inhibiter at370° C., adjusting the water content of the hydrous oxide to a lowerlevel and adding ammonium paramolybdate as a particle growth inhibiterin an amount corresponding to 16.3 wt % of titanium oxide on the oxidebasis.

[0214] The properties of the catalyst thus obtained are shown in Table10. TABLE 10 Comparative Comparative Example 9 Example 10 Raw materialspecies TiCl₄ TiCl₄ x in composition formula 0.53 0.01 y in compositionformula — 0 Properties Specific surface area (m²/g) 71 54 Pore volume(TPV) (ml/g) 0.36 0.41 Pore sharpness degree (%) 51 45

EXAMPLE 27

[0215] (Step for Synthesis of Hydrous Titanium Oxide Particles)

[0216] To 10 kg of pure water was added 1500 g of an aqueous solution oftitanium tetrachloride with a concentration of 210 g/l to adjust the pHof the synthesis solution to 0.5 and then 2300 g of 14 wt % ammoniawater was added to shift the pH to 7.0 and give a hydrosol slurry ofhydrous titanium oxide. The temperature during this synthesis was 80° C.

[0217] To the hydrosol slurry of hydrous titanium oxide thus obtainedwas added 1500 g of an aqueous solution of titanium tetrachloride with aconcentration of 500 g/l to return the pH of the slurry to 0.5 in theacid range of hydrous titanium oxide hydrosol dissolving pH range), then2800 ml of 14 wt % ammonia water was added to return the pH of theslurry to 7.0 (hydrosol precipitating pH range), this pH swing operationwas repeated five times in total, the hydrogel was filtered and theresulting cake was washed with pure water repeatedly until the absenceof chlorine ion (Cl⁻) was confirmed by titration with silver nitrate,and the cake was filtered and dehydrated at room temperature until thewater content (structural water+free water) became approximately 300 wt% on the solid basis to give a dehydrated hydrogel of hydrous titaniumoxide.

[0218] (Ion Exchange with Ions Containing Catalyst Components)

[0219] To the hydrogel of hydrous titanium oxide thus obtained was addedan aqueous solution containing 30 wt % of ammomum paramolybdate[(NH₄)₆Mo₇O₂₄.6H₂O], 4 wt % of phosphoric acid (H₃PO₄) and 4 wt % ofcobalt nitrate [Co(NO₃)₂.6H₂O] and the mixture was kneaded in a kneaderat room temperature for 2 hours to give an ion-exchanged intimatemixture.

[0220] (Molding, Drying and Calcining of Catalyst)

[0221] The mixture was molded into a cylindrical form by the use of a2.4 mm-diameter die, the molded form was dried at 120° C. for 3 hoursand then calcined at 500° C. for 3 hours to give a hydrotreatingcatalyst composed of the catalyst components supported on titaniumoxide.

[0222] The properties of the hydrotreating catalyst obtained in Example46 are shown in Table 11.

EXAMPLE 28

[0223] A hydrotreating catalyst composed of the catalyst componentssupported on titanium oxide was prepared as in the aforementionedExample 27 with the exception of preparing a hydrogel of hydroustitanium oxide by adding an aqueous solution of titanium tetrachlorideand an aqueous solution of ammonia without performing a pH swingoperation and then adding to this hydrogel of hydrous titanium oxide theions of the catalyst yielding 37 wt % of molybdenum (MoO₃), 5 wt % ofcobalt (CoO) and 5 wt % of phosphorus (P₂O₅) on the oxide basis.

[0224] The properties of the hydrotreating catalyst obtained in Example28 are shown in Table 11.

EXAMPLE 29

[0225] A hydrotreating catalyst composed of the catalyst componentssupported on titanium oxide was prepared as in the aforementionedExample 27 with the exception of preparing a hydrogel of hydroustitanium oxide by repeating the procedure of adding an aqueous solutionof titanium tetrachloride and an aqueous solution of ammonia (pH swingoperation) seven times in total and then adding to this hydrogel ofhydrous titanium oxide the ions of the catalyst components yielding 20wt % of molybdenum (MoO₃), 4 wt % of cobalt (CoO) and 7 wt % ofphosphorus (P₂O₅) on the oxide basis.

[0226] The properties of the hydrotreating catalyst obtained in Example29 are shown in Table 11.

EXAMPLE 30

[0227] A hydrotreating catalyst composed of the catalyst componentssupported on titanium oxide was prepared as in the aforementionedExample 27 with the exception of preparing a hydrogel of hydroustitanium oxide by repeating the procedure of adding an aqueous solutionof titanium tetrachloride and an aqueous solution of ammonia (pH swingoperation) 12 times in total and then adding to this hydrogel of hydroustitanium oxide the ions of the catalyst components yielding 23 wt % ofmolybdenum MoO₃), 4 wt % of cobalt (CoO) and 5 wt % of phosphorus (P₂O₅)on the oxide basis.

[0228] The properties of the hydrotreating catalyst obtained in Example30 are shown in Table 11.

EXAMPLE 31

[0229] A hydrotreating catalyst composed of the catalyst componentssupported on titanium oxide was prepared as in the aforementionedExample 27 with the exception of preparing a hydrogel of hydroustitanium oxide by repeating the procedure of adding an aqueous solutionof titanium tetrachloride and an aqueous solution of ammonia (pH swingoperation) four times in total and then adding to this hydrogel ofhydrous titanium oxide the ions of the catalyst components yielding 25wt % of tungsten (WO₃) and 5 wt % of cobalt (CoO) on the oxide basis.

[0230] The properties of the hydrotreating catalyst obtained in Example31 are shown in Table 11.

EXAMPLE 32

[0231] A hydrotreating catalyst composed of the catalyst componentssupported on titanium oxide was prepared as in the aforementionedExample 27 with the exception of preparing a hydrogel of hydroustitanium oxide by repeating the procedure of adding an aqueous solutionof titanium tetrachloride and an aqueous solution of ammonia (pH swingoperation) seven times in total and then adding to this hydrogel ofhydrous titanium oxide the ions of the catalyst components yielding 30wt % of molybdenum (MoO₃), 4 wt % of cobalt (CoO) and 3 wt % of boron(B₂O) on the oxide basis.

[0232] The properties of the hydrotreating catalyst obtained in Example32 are shown in Table 11. TABLE 11 Example Example Example ExampleExample Exam- 27 28 29 30 31 ple 32 Raw material species TiCl₄ TiCl₄TiCl₄ TiCl₄ TiCl₄ TiCl₄ x in composition formula 0.33 1.83 0.24 0.150.34 0.28 y in composition formula 13.0 11.5 13.1 13.1 13.0 13.0Properties Specific surface area (m²/g) 112 121 156 132 113 141 Porevolume (TPV) (ml/g) 0.35 0.23 0.47 0.26 0.32 0.33 Pore sharpness degree(%) 70 80 54 52 70 65 Results of reaction Relative desulfurizationactivity (—) 2.6 3.4 2.0 2.3 2.0 2.3 Relative denitrification activity(—) 3.5 4.3 2.9 3.4 3.0 3.2 Hydrogen consumption (NI/l) 42 44 38 41 — —

COMPARATIVE EXAMPLE 11

[0233] The catalyst used was a commercial cobalt-molybdenum-phosphoruscatalyst supported on alumina (5.1 wt % CoO/20.0 wt % MoO₃/1.1 wt %P₂O₅) with a BET specific surface area of 241 m²/g for use in deephydrodesulfurization of gas oil.

[0234] The properties of the hydrotreating catalyt used in ComparativeExample 11 are shown in Table 12.

COMPARATIVE EXAMPLE 12

[0235] The catalyst used was a commercial nickel-molybdenum catalystsupported on alumina (3.6 wt % NiO/20.4 wt % MoO₃) with a BET specificsurface area of 241 m²/g for use in deep hydrodesulfurization of gas oiland differed in composition of the catalyst components from the one inthe aforementioned Comparative Example 11.

[0236] The properties of the hydrotreating catalyt used in ComparativeExample 12 are shown in Table 12.

COMPARATIVE EXAMPLE 13

[0237] The hydrogel of hydrous titanium oxide obtained in Example 27 wasmolded, the molded form was dried at 120° C. for 3 hours and thencalcined at 500° C. for 3 hours, the calcined form was impregnated withthe same aqueous solution (of the ions containing the catalystcomponents) as used in Example 27, dried at 120° C. for 3 hours and thencalcined at 500° C. for 3 hours to give a hydrotreating catalystcomposed of the catalyst components supported on titanium oxide.

[0238] The properties of the hydrotreating catalyt obtained inComparative Example 13 are shown in Table 12.

COMPARATIVE EXAMPLE 14

[0239] A hydrotreating catalyst composed of the catalyst componentssupported on titanium oxide was prepared as in the aforementionedExample 27 with the exception of preparing a hydrogel of hydroustitanium oxide by repeating the procedure of adding an aqueous solutionof titanium tetrachloride and an aqueous solution of ammonia (pH swingoperation) 20 times in total and then adding to this hydrogel of hydroustitanium oxide the ions of the catalyst components yielding 28 wt % ofmolybdenum (MoO₃), 4 wt % of cobalt (CoO) and 4 wt % of phosphorus P₂O₅)on the oxide basis.

[0240] The properties of the hydrotreating catalyst obtained inComparative Example 14 are shown in Table 12.

COMPARATIVE EXAMPLES 15

[0241] A hydrotreating catalyst composed of the catalyst componentssupported on titanium oxide was prepared as in the aforementionedExample 27 with the exception of preparing a hydrogel of hydroustitanium oxide by repeating the procedure of adding an aqueous solutionof titanium tetrachloride and an aqueous solution of ammonia (pH swingoperation) seven times in total and then adding to this hydrogel ofhydrous titanium oxide the ions of the catalyst components yielding 14wt % of molybdenum (MoO₃), 4 wt % of cobalt (CoO) and 3 wt % ofphosphorus (P₂O₅) on the oxide basis.

[0242] The properties of the hydrotreating catalyst obtained inComparative Example 15 are shown in Table 12. TABLE 12 ComparativeComparative Comparative Comparative Comparative Example 11 Example 12Example 13 Example 14 Example 15 Raw material species — — TiCl₄ TiCl₄TiCl₄ x in composition formula — — 0.01 0.12 0.25 y in compositionformula — — 0 13.2 13 Properties Specific surface area (m²/g) 241 237110 66 165 Pore volume (TPV) (ml/g) 0.51 0.41 0.36 0.22 0.48 Poresharpness degree (%) — — 68.2 46.2 53.8 Results of reaction Relativedesulfurization (—) 1.0 1.1 1.3 1.2 0.8 activity Relativedenitrification (—) 1.0 2.1 2.3 1.9 1.9 activity Hydrogen consumption(NI/l) 41 53 — — 38

TEST EXAMPLE 1 Hydrotreating Test of Light Gas Oil

[0243] The tests were conducted on hydrotreating of Middle Eaststraight-run light gas oil by the use of the hydrotreating catalysts ofExample 27 and Comparative Example 11 and the performance of thecatalyst was examined. The light gas oil has the following properties:specific gravity (15/4° C.), 0.850; sulfur contents, 1.37 wt %; nitrogencontents, 101 ppm; distillation properties, initial boiling point 232°C., 50% boiling point 295° C., 90% boiling point 348° C.

[0244] The light gas oil was subjected to a hydrotreating in ahigh-pressure flow type reactor under the following conditions: reactionpressure, 5.0 MPa; reaction temperature, 350° C.; liquid hourly spacevelocity, 2.0 hr⁻¹; hydrogen/oil ratio, 250 Nl/l. All the catalysts usedin the tests were submitted to presulfiding by the use of light gas oilwhose content of sulfur components had been adjusted to 2.5 wt % byadding dimethyl disulfide.

[0245] Regarding the results of the hydroprocessing tests, the reactionrate constant was obtained while regarding the desulfurization reactionas 1.2th order reaction and the denitrogenation reaction as the 1storder reaction and the results were expressed in a relative value withthe results of Comparative Example 1 taken as “1.0.” Moreover, theconsumption of hydrogen (Nl/l) was obtained.

[0246] The results are shown in Tables 11 and 12.

[0247] (Relationship Between Nitrogen Removal and Hydrogen Consumption)

[0248] The relationship between the degree of nitrogen removal and theconsumption of hydrogen was investigated on the catalysts composed ofthe catalyst components supported on titanium oxide (titania catalysts)of the aforementioned Examples 27 through 30 and the alumina catalystsof Comparative Examples 11 and 12. The results are shown in Tables 11and 12.

[0249] As is apparent from Tables 11 and 12, the catalysts of thisinvention in Examples 27 through 30 show the denitrogenation activityapproximately three times as high as that of the Co/Mo catalystsupported on alumina of Comparative Example 11 and yet consume acomparable amount of hydrogen; further, they show the denitrogenationactivity approximately 1.5 times as high as that of the Ni/Mo catalystsupported on alumina of Comparative Example 12 which is considered toshow a relatively high hydrotreating activity, and yet their consumptionof hydrogen is lower by 10 Nl/l than the Ni/Mo/alumina catalyst.

[0250] Thus, it is clear that the titania catalysts of Examples 27through 30 can sharply reduce the consumption of hydrogen.

[0251] (Relationship Between Sulfur Removal and Nitrogen Removal)

[0252] The relationship between the degree of sulfur removal and thedegree of nitrogen removal was investigated on the catalysts composed ofthe catalyst components supported on titanium oxide (titania catalysts)of the aforementioned Examples 27 through 30, the Co/Mo/alumina catalystof Comparative Example 11 and the Ni/Mo/alumina catalyst of ComparativeExample 12.

[0253] As the results shown in FIG. 4 indicate, the titania catalysts ofthe Examples are highly selective toward denitrogenation and they aresuitable for use as a hydrotreating catalyst in hydroprocessing aimed atboth desulfurization and denitrogenation.

EXAMPLE 33

[0254] (Step for Synthesis of Hydrous Titanium Oxide Particles)

[0255] To 10 kg of pure water was added 1500 g of an aqueous solution oftitanium tetrachloride with a concentration of 210 g/l to adjust the pHof the synthesis solution to 0.5 and then 2300 g of 14 wt % ammoniawater was added to shift the pH to 7.0 and give a hydrosol slurry ofhydrous titanium oxide. The temperature during this synthesis was 60° C.

[0256] To the hydrosol slurry of hydrous titanium oxide thus obtainedwas added 1500 g of an aqueous solution of titanium tetrachloride with aconcentration of 500 g/l to return the pH of the slurry to 0.5 in theacid range of hydrous titanium oxide hydrosol dissolving pH range), then2800 ml of 14 wt % ammonia water was added to return the pH of theslurry to 7.0 (hydrosol precipitating pH range), this pH swing operationwas repeated three times in total, the hydrogel was filtered and theresulting cake was washed with pure water repeatedly until the absenceof chlorine ion (Cl⁻) was confirmed by titration with silver nitrate,and the cake was filtered and dehydrated at room temperature until thewater content (structural water+free water) became approximately 300 wt% on the solid basis to give a dehydrated hydrogel of hydrous titaniumoxide.

[0257] (Ion Exchange with Ions Containing Catalyst Components)

[0258] To the hydrous titanium oxide obtained above were added 0.26 atomof ammonium paramolybdate [(NH₄)₆Mo₇O₂₄.4H₂O], 0.05 atom of phosphoricacid (H₃PO₄) and 0.06 atom of cobalt nitrate [Co(NO₃)₂.6H₂O] per 1 atomof titanium and the mixture was kneaded in a kneader at room temperaturefor 2 hours. The pH at this time was 6.5.

[0259] (Molding, Drying and Calcining)

[0260] The hydrous titanium oxide ion-exchanged with the catalystcomponents was molded into a cylindrical form by the use of a 2.4mm-diameter die, the molded form was dried at 120° C. for 3 hours andthen calcined at 500° C. for 3 hours to give a hydrotreating catalyst ofExample 33. The properties of this hydrotreating catalyst are shown inTable 13.

EXAMPLE 34

[0261] The hydrous titanium oxide obtained in Example 33 was thrown intoa solution of pH 9 containing 0.47 atom of ammonium paramolybdate[(NH₄)Mo₇O₂₄.4H₂O], 0.06 atom of phosphoric acid (H₃PO₄) and 0.10 atomof cobalt nitrate [Co(NO₃)₂.6H₂O] per 1 atom of titanium and dispersedwith stirring for 3 hours to effect an ion exchange.

[0262] Thereafter, the ion-exchanged hydrous titanium oxide wasfiltered, dehydrated and processed as in Example 55 to give ahydrotreating catalyst of Example 34. The properties of the catalystobtained are shown in Table 13.

EXAMPLE 35

[0263] Hydrous titanium oxide was synthesized as in the aforementionedExample 33 with the exception of synthesizing hydrous titanium oxide byswinging the pH alternately between the hydrous titanium oxidedissolving pH range (pH=0.5) and the precipitating pH range (pH=7.0)seven times. The hydrous titanium oxide was filtered by compression togive a cake of hydrous titanium oxide with a water content (structuralwater+free water) of approximately 10 wt % on the solid basis.

[0264] To this hydrous titanium oxide were added 0.16 atom of ammoniumparamolybdate [(NH₄)₆Mo₇O₂₄.4H₂O], 0.11 atom of phosphoric acid ([H₃PO₄)and 0.06 atom of cobalt nitrate [Co(NO₃)₂.6H₂O] per 1 atom of titaniumand the mixture was processed as in Example 33 to give a hydrotreatingcatalyst of Example 35.

[0265] The properties of this catalyst are shown in Table 13.

EXAMPLE 36

[0266] Hydrous titanium oxide was synthesized as in Example 33, washed,filtered and dehydrated in a vacuum filter. The water content(structural water+free water) of the hydrous titanium oxide thusobtained was approximately 400 wt % on the solid basis. To this hydroustitanium oxide were added 0.16 atom of ammonium paramolybdate[(NH₄)₆Mo₇O₂₄.4HO], 0.12 atom of phosphoric acid (H₃PO₄) and 0.05 atomof cobalt nitrate [Co(NO₃)₂.6H₂O] per 1 atom of titanium and the mixturewas processed as in Example 33 to give a hydrotreating catalyst. Theproperties of this catalyst are shown in Table 13.

EXAMPLE 37

[0267] A hydrotreating catalyst was prepared as in the aforementionedExample 33 with the exception of adding to the hydrous titanium oxide0.12 atom of ammonium tungstate [(NH₄)₂WO₄] and 0.08 atom of cobaltnitrate [Co(NO₃)₂.6H₂O] per 1 atom of titanium. The properties of thiscatalyst are shown in Table 13.

EXAMPLE 38

[0268] A hydrotreating catalyst was prepared as in the aforementionedExample 33 with the exception of adding to the hydrous titanium oxide0.38 atom of ammonium paramolybdate [(NH₄)₆Mo₇O₂₄.4H₂O], 0.16 atom ofboric acid (H₃BO₃) and 0.06 atom of cobalt nitrate [Co(NO₃)₂.6H₂O] per 1atom of titanium. The properties of this catalyst are shown in Table 13.

[0269] Furthermore, the hydrotreating catalyst obtained in Example 38here was submitted to electron probe microanalysis (EPMA) with the aidof an instrument JXA-8900 available from JOEL Ltd. The results shown inFIG. 5 indicate that 0.38 atom of molybdenum is supported on 1 atom oftitanium and, in spite of this high rate, molybdenum is supporteduniformly in the pores.

[0270] Furthermore, X-ray diffraction patterns were measured on thehydrotreating catalyst obtained in Example 38 and molybdenum oxide(MoO₃) with the aid of an X-ray difractomer PW3710 available fromPhillip. The hydrotreating catalyst of Example 38 gave the results shownin FIG. 6 while molybdenum oxide (MoO₃) gave the results shown in FIG.7. In the former, if molybdenum were present as molybdenum oxide (MoO₃)on the catalyst carrier, a diffraction pattern of MoO₃ would be bound toappear. However, no such diffraction pattern is observed for thecatalyst of Example 38 shown in FIG. 6. This indicates that molybdenumis coordinated to titanium oxide crystals and not merely present inlayers on the surface of the catalyst carrier.

COMPARATIVE EXAMPLE 16

[0271] Hydrous titanium oxide was synthesized as in Example 33 with theexception of preparing hydrous titanium oxide by setting the synthesistemperature at 95° C. and swinging the pH alternately between thehydrous titanium oxide dissolving pH range (pH=0.5) and theprecipitating pH range (pH=7.0) nine times. The hydrous titanium oxidethus obtained was washed, filtered and dried at 120° C. for 10 hours.

[0272] The water content (structural water+free water) of the driedhydrous titanium oxide was 0.5 wt % on the solid basis.

[0273] A hydrotreating catalyst was prepared as in Example 52 from thehydrous titanium oxide obtained above. The properties of this catalystare shown in Table 14.

COMPARATIVE EXAMPLE 17

[0274] To a 30-l vessel equipped with a stirrer was introduced 10 l ofwater, 1.5 l of the aqueous solution of titanium tetrachloride preparedin Example 55 was added with stirring to lower the pH to 0.5. To thissolution was added 2.3 l of 14 wt % ammonia water to raise the pH to 7.0and stirred there for approximately 5 minutes. The precipitate therebyformed was washed and filtered to give hydrous titanium oxide.

[0275] This hydrosol is amorphous and its water content (structuralwater+free water) was approximately 1000 wt % on the solid basis.

[0276] This hydrosol could not be molded because of its too high watercontent.

COMPARATIVE EXAMPLE 18

[0277] A hydrotreating catalyst was prepared as in the aforementionedExample 33 with the exception of adding 0.05 atom of ammonium tungstate[(NH₄)₂WO₄] and 0.019 atom of cobalt nitrate [Co(NO₃)₂.6H₂O] per 1 atomof titanium. The properties of the catalyst obtained are shown in Table14.

COMPARATIVE EXAMPLE 19

[0278] A hydrotreating catalyst was prepared as in the aforementionedExample 33 with the exception of adding 0.62 atom of ammoniumparamolybdate [(NH₄)₆Mo₇O₂₄.4H₂O] and 0.27 atom of cobalt nitrate[Co(NO₃)₂.6H₂O] per 1 atom of titanium. The properties of the catalystobtained are shown in Table 14.

TEST EXAMPLE 2 Hydrotreating Test of Light Gas Oil

[0279] The tests were conducted on hydrotreating of Middle Eaststraight-run light gas oil by the use of the hydrotreating catalysts ofthe aforementioned Examples 33 through 38 and Comparative Examples 11,12, 16 and 18 and the performance of the catalyst was examined. Thelight gas oil has the following properties: specific gravity (15/4° C.),0.850; sulfur contents, 1.37 wt %; nitrogen contents, 101 ppm;distillation properties, initial boiling point 232° C., 50% boilingpoint 295° C., 90% boiling point 348° C.

[0280] The light gas oil was hydrotreated in a flow type reactor underthe following conditions: reaction pressure, 5.0 MPa; reactiontemperature, 350° C.; liquid hourly space velocity, 2.0 hr⁻¹;hydrogen/oil ratio, 250 Nl/l. In these hydrotreating tests, thecatalysts were submitted to presulfiding by the use of light gas oilwhose content of sulfur components had been adjusted to 2.5 wt % byadding dimethyl disulfide.

[0281] Regarding the results of the hydroprocessing tests, the reactionrate constant was obtained while regarding the desulfurization reactionas 1.2th order reaction and the denitrogenation reaction as the 1storder reaction and the results were expressed in a relative value withthe results of Comparative Example 1 taken as “1.” The results are shownin Tables 13 and 14. TABLE 13 Example Example Example Example ExampleExam- 33 34 35 36 37 ple 38 Raw material species TiCl₄ TiCl₄ TiCl₄ TiCl₄TiCl₄ TiCl₄ x in composition formula 0.67 0.67 0.50 0.98 0.67 0.67 y incomposition formula 5.75 5.75 0.39 17.74 5.75 5.75 Properties Specificsurface area (m²/g) 102 156 154 155 157 156 Pore volume (TPV) (ml/g)0.35 0.47 0.46 0.47 0.40 0.49 Pore sharpness degree (%) 54 70 55 54 6059 Results of reaction Relative desulfurization activity (—) 2.5 2.3 2.12.0 2.0 2.5 Relative denitrification activity (—) 3.5 3.3 3.0 3.2 3.03.3

[0282] TABLE 14 Comparative Comparative Comparative Comparative Example16 Example 17 Example 18 Example 19 Raw material species TiCl₄ TiCl₄TiCl₄ TiCl₄ x in composition formula 0.14 1.11 0.67 0.67 y incomposition formula 0.02 27.1 5.75 5.75 Properties Specific surface area(m²/g) 65 — 113 50 Pore volume (TPV) (ml/g) 0.63 — 0.39 0.19 Poresharpness degree (%) 42 — 55 49 Results of reaction Relativedesulfurization activity (—) 1.2 — 0.8 1.3 Relative denitrificationactivity (—) 2.1 — 1.8 2.2

[0283] (Relationship Between Degree of Nitrogen Removal and Consumptionof Hydrogen)

[0284] The relationship between the degree of nitrogen removal and theconsumption of hydrogen was investigated by the use of the hydrotreatingcatalysts (titania catalysts) of the aforementioned Examples 52 and 53and the commercial catalysts (alumina catalysts) of Comparative Examples22 and 23 while varying the liquid hourly space velocity in the rangefrom 1 to 3 hr⁻¹. The results are shown in FIG. 8 and it is seen thatthe consumption of hydrogen can be reduced sharply in the case of thetitania catalysts of Examples 33 and 34.

[0285] (Explanation of Examples and Comparative Examples)

[0286] As is apparent from the results shown in Tables 13 and 14relating to the aforementioned Test Example 2, the hydrotreatingcatalysts of Examples 33 through 38 show the desulfurization activityapproximately twice or more and, in addition, the denitrogenationactivity approximately three times or more that of the commercialcatalyst of Comparative Example 11. Furthermore, they show approximately1.8-fold desulfurization activity or more and approximately 1.5-folddenitrogenation activity or more compared with the commercial catalystof Comparative Example 12. For all that, FIG. 8 shows that they consumeless hydrogen than the catalysts of Comparative Examples of 11 and 12.

[0287] The results in Comparative Examples 16 through 19 indicate that,in the case where the content of structural water and free water ofhydrous titanium oxide is small (Comparative Example 16), an ionexchange with the catalyst components does not proceed sufficiently andboth the desulfurization activity and the denitrogenation activity arenot sufficient and on the same order as those in Comparative Example 19.On the other hand, in the case where the content of structural water andfree water is excessively large (Comparative Example 17), the moldingoperation required for the preparation of catalysts cannot be performed.Moreover, in the case where the amounts of the principal catalystcomponent tungsten and the promoter component nickel supported on thecarrier are insufficient (Comparative Example 18), no improvement indesulfurization activity was observed. Still further, in the case wherethe amount of the principal catalyst component molybdenum is excessive(Comparative Example 19), such excess was found to be not effective forimproving the desulfurization activity and the denitrogenation activity.

[0288] Industrial Applicability

[0289] According to this invention, it is possible to prepare easily aporous 4 group metal oxide which not only has a large specific surfacearea but also exhibits excellent heat stability. Moreover, it ispossible to prepare easily a porous 4 group metal oxide which ischaracterized by excellent reaction selectivity, a large specificsurface area, high catalytic activity and excellent heat stability anduseful for a catalyst or a catalyst carrier based on a 4 group metal bythe use of a hydrosol of a hydrous 4 group metal oxide having acontrolled and sharp pore distribution.

[0290] Furthermore, high-purity porous titanium oxide of this inventionhas properties such as a large specific surface area, excellent heatstability, precisely controlled pore diameter and sharp poredistribution and is useful for applications specifically requiringtitanium oxide as a catalyst or a catalyst carrier.

[0291] Further, according to this invention, it is possible to prepareporous titanium oxide which is controlled to have pore distribution in ashape conforming to the molecular weight distribution of the reactantsat an arbitrary pore diameter, has a larger specific surface area thanporous titanium oxide in uniform spherical particles and exhibitsexcellent mechanical strength and it is possible to prepare poroustitanium oxide which is tailored to the purpose and use as a catalystcarrier or a catalyst.

[0292] According to this invention, it is possible to provide ahydrotreating catalyst with excellent performance in desulfurization anddenitrogenation with minimal consumption of hydrogen and the catalyst issuitable not only for hydroprocessing of hydrocarbon oils, particularlyof gas oil and the like which require superdeep desulfurization and deepdenitrogenation, but also advantageously applicable to hydroprocessinginvolving lower degrees of desulfurization and denitrogenation of otherhydrocarbon oils.

1. A porous 4 group metal oxide which is characterized in that it isprepared by adding a particle growth inhibiter to a hydrosol, a hydrogelor a dried product of a hydrous 4 group metal oxide represented by thegeneral formula MO_((2-x)) (OH)_(2x) (wherein M denotes a 4 group metaland x is a number greater than 0.1 or x>0.1) followed by drying andcalcining and has a specific surface area of 80 m²/g, a pore volume of0.2 ml/g or more and a pore sharpness degree of 50% or more.
 2. A porous4 group metal oxide as described in claim 1 wherein the 4 group metal Mis titanium (Ti).
 3. A porous 4 group metal oxide as described in claim1 wherein the 4 group metal M is zirconium (Zr).
 4. A porous 4 groupmetal oxide as described in claim 1 wherein the hydrous 4 group metaloxide is hydrous titanium oxide represented by the composition formulaTiO_((2-x)) (OH)_(2x).yH₂O (wherein 0.1≦x<2.0 and 0.3≦y≦40).
 5. A porous4 group metal oxide as described in claim 1 wherein the hydrous 4 groupmetal oxide is hydrous titanium oxide represented by the compositionformula TiO_((2-x)) (OH)_(2x).yH₂O (wherein 0.2≦x<1.0 and 0.3≦y≦40). 6.A porous 4 group metal oxide as described in any one of claims 1 through5 wherein the hydrous 4 group metal oxide is prepared by using a 4 groupmetal compound as a raw material and a pH adjusting agent and performinga pH swing operation alternately plural times between the precipitatingpH range and the dissolving pH range of the hydrous 4 group metal oxidein a synthesis solvent.
 7. A porous 4 group metal oxide as described inany one of claims 1 through 5 wherein the 4 group metal M is titanium(Ti) and the hydrous titanium oxide is synthesized by using a rawmaterial titanium compound and a pH adjusting agent and performing a pHswing operation in a synthesis solvent in the non-dissolving pH range ofthe hydrous titanium oxide alternately plural times between the range onthe low pH side (1<pH≦4) and the pH range near the isoelectric point ofthe hydrous titanium oxide (5.1≦pH≦7.1) or between the pH range near theisoelectric point of the hydrous titanium oxide (5.1≦pH≦7.1) and therange on the high pH side (8≦pH≦12).
 8. A porous 4 group metal oxide asdescribed in any one of claims 1 through 5 wherein the 4 group metal Mis titanium (Ti) and the hydrous titanium oxide is synthesized by usinga raw material titanium compound and a pH adjusting agent and performinga pH swing operation in a synthesis solvent in the non-dissolving pHrange of the hydrous titanium oxide between the range on the low pH side(1<pH≦4) and the range across the pH range near the isoelectric point ofthe hydrous titanium oxide (5.1≦pH≦7.1) or between the range on the highpH side (8≦pH≦12) and the range across the pH range near the isoelectricpoint of the hydrous titanium oxide (5.1≦pH≦7.1) while allowing asufficient aging time for growth of particles in the pH range near theisoelectric point (5.1≦pH≦7.1).
 9. A porous 4 group metal oxide asdescribed in any one of claims 1 through 5 wherein the metal oxide ishydrous titanium oxide and wherein the pore asymmetric coefficient N ofthe hydrous titanium oxide defined by N=(A−C)/(B−A) (wherein A is thelogarithmic value of the median diameter, B is the logarithmic value ofthe pore diameter of the 2% pore volume and C is the logarithmic valueof the pore diameter of the 98% pore volume) falls in the range of1.5≦N≦4.
 10. A porous 4 group metal oxide as described in any one ofclaims 1 through 5 wherein the particle growth inhibiter is a compoundyielding ions containing an element selected from silicon (Si),phosphorus (P), magnesium (Mg), calcium (Ca), manganese (Mn), aluminum(Al) and zirconium (Zr).
 11. A porous 4 group metal oxide as describedin any one of claims 1 through 5 wherein the particle growth inhibiteris a compound yielding ions containing an element selected from sulfur(S), molybdenum (Mo), tungsten (W), vanadium (V) and boron (B).
 12. Aporous 4 group metal oxide as described in any one of claims 1 through 5wherein the particle growth inhibiter is a compound yielding ionscontaining an element selected from iron (Fe), nickel (Ni), cobalt (Co),platinum (Pt), palladium (Pd), rhodium (Rh) and ruthenium (Ru).
 13. Aporous 4 group metal oxide described in any one of claims 1 through 5wherein the particle growth inhibiter is added together with the 4 groupmetal compound as a raw material to the reaction solvent during thesynthesis of the hydrous 4 group metal oxide, after the synthesis andbefore the dehydration of the hydrous 4 group metal oxide, or after thedehydration and before the calcination of the hydrous 4 group metaloxide.
 14. A porous 4 group metal oxide as described in any one ofclaims 1 through 5 wherein the particle growth inhibiter is added in thesteps for filtration and washing of the hydrous 4 group metal oxide. 15.A porous 4 group metal oxide as described in any one of claims 1 through5 wherein the particle growth inhibiter is added at a pH less than theisoelectric point of the hydrous 4 group metal oxide in case it isanions, added at a pH more than the isoelectric point in case it iscations or added at a pH corresponding to the isoelectric point ±1.0 incase it is simultaneously anions and cations.
 16. A porous 4 group metaloxide described in any one of claims 1 through 5 wherein the elementcontained in the particle growth inhibiter has catalytic activity forhydrotreating and the hydroxyl groups of the hydrous 4 group metal oxideare exchanged by the ions of said element.
 17. A porous 4 group metaloxide as described in claims 1 through 5 wherein the porous 4 groupmetal oxide has a purity of 97 wt % or more on the oxide (MO₂) basis.18. A porous 4 group metal oxide as described in claim 17 wherein theelement originating in the particle growth inhibiter is contained in therange from 0.1 wt % to not more than 3 wt % on the oxide basis.
 19. Amethod for preparing a porous 4 group metal oxide which comprises addinga particle growth inhibiter to a hydrosol, a hydrogel or a dried productof a hydrous 4 group metal oxide obtained by the reaction of a 4 groupmetal compound as a raw material with a pH adjusting agent in an aqueoussolvent and represented by the general formula MO_((2-x))(OH)_(2x)(wherein M denotes a 4 group metal and x is a number greater than 0.1 orx>0.1) followed by drying and calcining thereby yielding a 4 group metaloxide which has a specific surface area of 80 m²/g or more, a porevolume of 0.2 ml/g or more and a pore sharpness degree of 50% or more.20. A method for preparing a porous 4 group metal oxide as described inclaim 19 wherein the hydrous 4 group metal oxide is hydrous titaniumoxide or the 4 group metal M is titanium (Ti).
 21. A method forpreparing a porous 4 group metal oxide as described in claim 19 whereinthe hydrous 4 group metal oxide is hydrous zirconium oxide or the 4group metal M is zirconium (Zr).
 22. A method for preparing a porous 4group metal oxide as described in claim 19 wherein the hydrous 4 groupmetal oxide is hydrous titanium oxide represented by the compositionformula TiO_((2-x))(OH)_(2x).yH₂O (wherein 0.1≦x<2.0 and 0.3≦y≦40). 23.A method for preparing a porous 4 group metal oxide as described inclaim 19 wherein the hydrous 4 group metal oxide is hydrous titaniumoxide represented by the composition formula TiO_((2-x))(OH)_(2x) .yH₂O(wherein 0.2≦x<1.0 and 0.3≦y≦40).
 24. A method for preparing a porous 4group metal oxide as described in any one of claims 19 through 23wherein the hydrous 4 group metal oxide is obtained by using a 4 groupmetal compound as a raw material and a pH adjusting agent and performinga pH swing operation alternately between the precipitating pH range andthe dissolving pH range of the hydrous 4 group metal oxide plural timesin a synthesis solvent.
 25. A method for preparing a porous 4 groupmetal oxide as described in any one of claims 19 through 23 wherein the4 group metal M is titanium (Ti) and hydrous titanium oxide issynthesized by using a raw material titanium compound and a pH adjustingagent and performing a pH swing operation in a synthesis solvent in thenon-dissolving pH range of the hydrous titanium oxide alternately pluraltimes between the range on the low pH side (1<pH≦4) and the pH rangenear the isoelectric point of the hydrous titanium oxide (5.1≦pH≦7.1) orbetween the pH range near the isoelectric point of the hydrous titaniumoxide (5.1≦pH≦7.1) and the range on the high pH side (8≦pH≦12).
 26. Amethod for preparing a porous 4 group metal oxide as described in anyone of claims 19 through 23 wherein the 4 group metal M is titanium (Ti)and hydrous titanium oxide is synthesized by using a raw materialtitanium compound and a pH adjusting agent and performing a pH swingoperation in a synthesis solvent in the non-dissolving pH range of thehydrous titanium oxide between the range on the low pH side (1<pH≦4) andthe range across the pH range near the isoelectric point (5.1≦pH≦7.1) orbetween the range on the high pH side (8≦pH≦12) and the range across thepH range near the isoelectric point (5.1≦pH≦7.1) while allowing asufficient aging time for growth of particles in the range near theisoelectric point (5.1≦pH≦7.1).
 27. A method for preparing a porous 4group metal oxide as described in any one of claims 19 through 23wherein the particle growth inhibiter is added together with the 4 groupmetal compound as a raw material to the reaction solvent during thesynthesis of the hydrous 4 group metal oxide, after the synthesis andbefore the dehydration of the hydrous 4 group metal oxide or after thedehydration and before the calcination of the hydrous 4 group metaloxide.
 28. A method for preparing a porous 4 group metal oxide asdescribed in any one of claims 19 through 23 wherein the particle growthinhibiter is added at a pH less than the isoelectric point of thehydrous 4 group metal oxide in case it is anions, added at a pH morethan the isoelectric point in case it is cations or added at a pHcorresponding to the isoelectric point ±1.0 in case it is simultaneouslyanions and cations.
 29. A method for preparing a porous 4 group metaloxide as described in any one of claims 19 through 23 wherein theparticle growth inhibiter is added in the steps for filtration andwashing of the hydrous 4 group metal oxide.
 30. A method for preparing aporous 4 group metal oxide as described in claim 29 wherein washingwater to be used in the steps for filtration and washing of the hydrous4 group metal oxide contains a particle growth inhibiter in an amount inthe range of 1-100 ppm on the oxide basis of the metal contained in theparticle growth inhibiter.
 31. A method for preparing a porous 4 groupmetal oxide as described in any one of claims 19 through 23 wherein themetal contained in a particle growth inhibiter has catalytic activityfor hydrotreating and the hydroxyl groups of the hydrous 4 group metaloxide are exchanged by the ions of this metal.
 32. A hydrotreatingcatalyst for hydrocarbon oils comprising the porous 4 group metal oxidedescribed in claim
 16. 33. A hydrotreating catalyst for hydrocarbon oilsas described in claim 32 wherein the 4 group metal M is titanium (Ti).34. A hydrotreating catalyst for hydrocarbon oils as described in claim32 wherein the element having catalytic activity for hydrotreating isthe principal catalyst element molybdenum (Mo) and/or tungsten (W) andone kind or more of promoter elements selected from 9, 10, 11, 13 and 15groups.
 35. A hydrotreating catalyst for hydrocarbon oils as describedin claim 34 wherein the promoter element is one kind or more of elementsselected from cobalt (Co), nickel (Ni), phosphorus (P) and boron (B).36. A hydrotreating catalyst for hydrocarbon oils as described in claim32 wherein the amount of ion exchange of the principal catalyst elementis 0.06-0.46 atom per 1 atom of titanium, that of the promoter elementis 0.02-0.26 atom per 1 atom of titanium and the sum total of theamounts of ion exchange of the principal catalyst element and thepromoter element is 0.08-0.82 atom per 1 atom of titanium.
 37. In thepreparation of the hydrotreating catalyst described in claim 32, amethod for preparing a hydrotreating catalyst for hydrocarbon oils whichcomprises bringing the hydrous 4 group metal oxide into contact with theions containing the principal catalyst element and the ions containingthe promoter element, either together or separately, to effect an ionexchange, finally regulating the pH in the range of 3-9, molding, dryingand calcining.
 38. In the preparation of the hydrotreating catalystdescribed in claim 32, a method for preparing a hydrotreating catalystfor hydrocarbon oils which comprises adding the hydrous 4 group metaloxide to a impregnating solution of the ions containing the principalcatalyst element and the ions containing the promoter element at pH 1-7or pH 9-11 to effect an ion exchange, filtering, molding, drying andcalcining.
 39. In the preparation of the hydrotreating catalystdescribed in claim 32, a method for preparing a hydrotreating catalystfor hydrocarbon oils which comprises effecting the ion exchangeinvolving the ions containing the principal catalyst element molybdenum(Mo) and/or tungsten (W) and the ions containing one kind or more of thepromoter elements selected from cobalt (Co), nickel (Ni), phosphorus (P)and boron (B), filtering, molding, drying and calcining.
 40. A methodfor hydrotreating of hydrocarbon oils which comprises contacting thehydrotreating catalyst described in claim 32 with hydrocarbon oils inthe presence of hydrogen at a reaction temperature of 280-400° C., areaction pressure of 2-15 MPa, an LHSV of 0.3-10 hr⁻¹ and a hydrogen/oilratio of 50-500 Nl/l to remove sulfur components and nitrogen componentsfrom the hydrocarbon oils.